Title of Invention: Transition metal-catalyzed protodecarboxylation of α-halo-acrylic acid derivatives Abstract: The present invention relates to a method for the synthesis of a halo olefin of formula (I) wherein Hal, R1, R2, R3, R4, X and Y are as defined herein, or a salt thereof. Detailed Description: Part general_description_paragraphs: Part FIELD OF THE INVENTION: The present invention relates to a method for the synthesis of a halo olefin of formula (I) wherein the substituents Hal, R1, R2, R3, R4, X and Y are defined as hereinafter, or a salt thereof comprising the step of the protodecarboxylation of an α-halo-acrylic acid derivative of formula (II) carried out in the presence of a catalytic amount of copper and/or silver. The present invention relates also to the intermediates comprised in the method according to this invention. Part BACKGROUND OF THE INVENTION: Terminal halo olefins are not only useful synthetic intermediates in organic chemistry, but also valuable target compounds themselves: There is a long-standing history of their use as monomers in polymer science (Marvel et al., J. Am. Chem. Soc. 1939, 61, 3241-3244), but more recently they have also attracted interest in the life sciences (e.g. Kolb et al., J. Med. Chem. 1987, 30, 267-272; Nunnery et al., J. Org. Chem. 2012, 77, 4198-4208; Akiyama et al., Tetrahedron 2013, 69, 6560-6564). In medicinal chemistry, for instance, terminal haloallylamine compounds have been reported to act as inhibitors of amine oxidases (WO 2005/082343, WO 2006/094201, WO 2007/120528, WO 501.761.4010). Terminal halo olefins are synthetically accessible by a limited number of approaches (van Steenis et al., J. Chem. Soc., Perkin Trans. 1, 2002, 2117-2133; Landelle et al., Chem. Soc. Rev. 2011, 40, 2867-2908; Koh et al., Nature 2016, 531, 459-465, Nguyen et al., Science 2016, 352, 569), e.g. by elimination, addition, electrophilic or nucleophilic halogenation, olefination (e.g. Wittig-type) reactions or cross-metathesis. However, the preparation of terminal halo olefins in high stereoselectivities is often one of the major challenges. The recent approaches for the terminal halo olefin formation within the context of amine oxidase inhibitor synthesis comprise a Wittig reaction, starting from ketones, followed by separation of the E/Z isomers via chromatographic techniques or recrystallization (WO 2005/082343, WO 2007/120528, WO 501.761.4010). In addition, a halogenation-dehydrohalogenation of olefins as well as the base-induced decarboxylative halogen elimination of halomethyl-substituted malonester derivatives have been disclosed (McDonald et al., J. Med. Chem. 1985, 28, 186-193; McDonald et al., Tetrahedron Letters 1985, 26, 3807-3810; WO 2005/082343, WO 2006/094201). One further approach for the formation of terminal halo olefins is the protodecarboxylation of α-halo-acrylic acid derivatives, which are accessible, e.g. by the Horner-Wadsworth-Emmons reaction starting from carbonyl species. However, the scope of this protodecarboxylation used to be limited to particular substrates, such as perfluorated acrylic acids or acrylic acids with unsaturated β-substituents: Sodium(I), silver(I) and copper(II) salts of perfluorated acrylic acid derivatives were reported to undergo protodecarboxylation upon substantial heating (Cherstkov et al., Izvestiya Akademii nauk SSSR, Seriya Khimicheskaya 1986, 1, 119-122; Cherstkov et al., Izvestiya Akademii nauk SSSR, Seriya Khimicheskaya 1989, 6, 1336-1340). Likewise, protodecarboxylation of mucohalic acids ((Z)-2-3-dihalo-4-oxo-2-butenoic acids, i.e. bearing a carbonyl substituent in β-position) to afford (Z)-α,β-dihaloacrolein can be effected by excessive heating (Duczek et al., Synthesis 1992, 10, 935-936). Acrylic acid derivatives with β-pyrimidinyl-substituents may be subject to protodecarboxylation by acidification at elevated temperatures (DD 259803). Acrylic acids with β-phenyl-substituents (i.e. cinnamic acid derivatives) can be decarboxylated by employment of copper(0)/copper(II)/quinoline and heating to above 200° C. (Elkik, Bull. Soc. Chim. Fr. 1967, 5, 1569-71), by using excessive copper(II) in the presence of molecular sieve in DMAC/DMSO at 140° C. (Rousée et al., Chem. Eur. J. 2014, 20, 15000-15004) or by cofactor catalysis (Payne et al., Nature 2015, 522, 497-501). In contrast, no single application of a protodecarboxylation step of acrylic acid derivatives with two vicinal saturated carbon substituents has been reported. In addition to the limited substrate scope, the use of stoichiometric amounts of metals and the heating to high temperatures constitute further drawbacks of the conversions reported to date, which have prevented a more widespread application of this reaction. Part SUMMARY OF THE INVENTION: In a first aspect, the present invention relates to a method for the synthesis of a halo olefin of formula (I) wherein Hal is selected from the group Hal-G1 consisting of F, Cl, Br and I, and R1, R2, R3 and R4 are independently selected from the group Ri-G1 consisting of H, halogen, CN, substituted or unsubstituted C1-10-alkyl, substituted or unsubstituted C3-10-cycloalkyl, substituted or unsubstituted C2-10-alkenyl, substituted or unsubstituted C2-10-alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted aryl-C1-6-alkylene-, substituted or unsubstituted heteroaryl and substituted or unsubstituted heteroaryl-C1-6-alkylene-, and X and Y are independently selected from the groups X-G1 and Y-G1, respectively, each consisting of Ri, ORX, SRX, S(O)RX, SO2RX, NRY1RY2, N(O)RY1RY2, PRY1RY2 and P(O)RY1RY2, wherein RX is selected from the group RX-G1 consisting of Ri, and wherein RY1 and RY2 are independently selected from the group RY-G1a consisting of Ri, C(O)Ri and C(O)ORi or RY1 and RY2 are selected from the group RY-G1b in which RY1 and RY2 are linked to form, together with N or P to which they are attached, substituted or unsubstituted heteroaryl or substituted or unsubstituted heterocyclyl, and Ri is selected from the group Ri-G1 as defined hereinbefore; or a salt thereof comprising the step (S1) (S1): protodecarboxylation of an α-halo-acrylic acid derivative of formula (II) wherein Hal, R1, R2, R3, R4, X and Y are defined as hereinbefore, and wherein (S1) is carried out in the presence of a catalytic amount of copper and/or silver. In a second aspect, the present invention relates to the intermediates that are comprised in the method according to the first aspect of the invention. Other aspects of the present invention will become apparent to the person skilled in the art directly from the foregoing and following description. Part DETAILED DESCRIPTION OF THE INVENTION: Part General Terms and Definitions: Unless otherwise stated, the groups, residues and substituents, particularly Hal, R, R0, R1, R2, R3, R4, Ri, RX, RY1, RY2, RN1, RN2, R, X and Y are defined as hereinbefore and hereinafter. If groups, residues or substituents occur several times in a compound or reaction scheme, they may have the same or different meanings. The terms “-G1”, “-G2,” etc., when added to the name of a residue or substituent, refer to different lists from which the particular residue or substituent may be selected). For example, the term RX-G1 denotes a first list from which RX may be selected. The elements of said lists are defined herein for each residue or substituent. Terms not specifically defined herein should be given the meanings that would be given to them by one of skill in the art in light of the disclosure and the context. As used in the specification, however, unless specified to the contrary, the following terms have the meaning indicated and the following conventions are adhered to. In the groups, radicals, or moieties defined below, the number of carbon atoms is often specified preceding the group, for example, C1-6-alkyl means an alkyl group or radical having 1 to 6 carbon atoms. In general, for groups comprising two or more subgroups, the last named subgroup is the radical attachment point, for example, the substituent “aryl-C1-3-alkylene-” means an aryl group which is bound to a C1-3-alkylene-group, the latter of which is bound to the core or to the group to which the substituent is attached. The term “C1-n-alkyl”, wherein n is an integer from 2 to n, either alone or in combination with another radical, denotes a monovalent acyclic, saturated, linear or branched hydrocarbon radical containing 1 to n C atoms. For example, the term C1-4-alkyl includes the radicals H3C—, H3C—CH2—, H3C—CH2—CH2—, H3C—CH(CH3)—, H3C—CH2—CH2—CH2—, H3C—CH2—CH(CH3)—, H3C—CH(CH3)—CH2—, H3C—C(CH3)2—. The term “C1-n-alkylene” wherein n is an integer from 2 to n, either alone or in combination with another radical, denotes a divalent acyclic, saturated, linear or branched hydrocarbon radical containing 1 to n C atoms. For example, the term C1-4-alkylene includes the radicals —CH2—, —CH2—CH2—, —CH(CH3)—, —CH2—CH2—CH2—, —C(CH3)2—, —CH(CH2CH3)—, —CH(CH3)—CH2—, —CH2—CH(CH3)—, —CH2—CH2—CH2—CH2—, —CH2—CH2—CH(CH3)—, —CH(CH3)—CH2—CH2—, —CH2—CH(CH3)—CH2—, —CH2—C(CH3)2—, —C(CH3)2—CH2—, —CH(CH3)—CH(CH3)—, —CH2—CH(CH2CH3)—, —CH(CH2CH3)—CH2—, —CH(CH2CH2CH3)—, —CH(CH(CH3))2— and —C(CH3)(CH2CH3)—. The term “C2-n-alkenyl”, wherein n is an integer from 3 to n, denotes a radical as defined for “C1-n-alkyl” with at least two C atoms, wherein at least two of the carbon atoms are bonded to each other by a double bond. The term “C2-n-alkynyl”, wherein n is an integer from 3 to n, denotes a radical as defined for “C1-n-alkyl” with at least two C atoms, wherein at least two of the carbon atoms are bonded to each other by a triple bond. The term “C3-n-cycloalkyl”, wherein n is an integer from 4 to n, either alone or in combination with another radical, denotes a cyclic, saturated, unbranched hydrocarbon radical containing 3 to n C atoms. For example, the term C3-7-cycloalkyl includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. The term “aryl”, either alone or in combination with another radical, denotes a carbocyclic aromatic monocyclic group containing 6 carbon atoms which may be further fused to a second 5- or 6-membered carbocyclic group which may be aromatic, saturated or unsaturated. Aryl includes, but is not limited to, phenyl, indanyl, indenyl, naphthyl, anthracenyl, phenanthrenyl, tetrahydronaphthyl and dihydronaphthyl. The term “heterocyclyl”, either alone or in combination with another radical, denotes a saturated or unsaturated mono- or polycyclic-ring system, including aromatic ring systems, containing one or more heteroatoms selected from N, O or S(O)r, wherein r=0, 1 or 2, consisting of 3 to 14 ring atoms wherein none of the heteroatoms is part of an aromatic ring. The term “heterocyclyl” is intended to include all the possible isomeric forms. The term “heteroaryl”, either alone or in combination with another radical, denotes a mono- or polycyclic ring system containing one or more heteroatoms selected from N, O or S(O)r, wherein r=0, 1 or 2, consisting of 5 to 14 ring atoms wherein at least one of the heteroatoms is part of an aromatic ring. The term “heteroaryl” is intended to include all the possible isomeric forms. The term halogen generally denotes fluorine, chlorine, bromine and iodine. The term “substituted” as used herein, means that any one or more hydrogens on the designated atom, radical or moiety are replaced by a further radical or moiety (“substituent”), provided that the atoms' normal valences are not exceeded, and that the substitution results in an acceptably stable compound. “Substituents” may be, but are not limited to halo, hydroxy, oxo, optionally halogenated alkoxy, amino, nitro, amidinyl, guanidinyl, sulfanyl, sulfo, sulfonyl, sulfonamido, silyl, optionally halogenated or hydroxylated alkyl or cycloalkyl or alkenyl, optionally halogenated or hydroxylated aryl or heteroaryl or heterocyclyl, cyano, carbonyl, acyl, alkoxycarbonyl, amido, carbamate and combinations thereof. As used herein, “pharmaceutically acceptable salt” refers to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. For example, such salts include salts from benzenesulfonic acid, benzoic acid, citric acid, ethanesulfonic acid, fumaric acid, gentisic acid, hydrobromic acid, hydrochloric acid, maleic acid, malic acid, malonic acid, mandelic acid, methanesulfonic acid, 4-methyl-benzenesulfonic acid, phosphoric acid, salicylic acid, succinic acid, sulfuric acid and tartaric acid. Further pharmaceutically acceptable salts can be formed with cations from ammonia, L-arginine, calcium, 2,2′-iminobisethanol, L-lysine, magnesium, N-methyl-D-glucamine, potassium, sodium and tris(hydroxy-methyl)-aminomethane. The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a sufficient amount of the appropriate base or acid in water or in an organic diluent like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile, or a mixture thereof. Salts of other acids than those mentioned above which for example are useful for purifying or isolating the compounds of the present invention (e.g. trifluoro acetate salts) also comprise a part of the invention. As noted above, the present invention discloses a method for the synthesis of halo olefins comprising the step of protodecarboxylation of α-halo-acrylic acid derivatives in the presence of a catalytic amount of copper and/or silver. In a first aspect, the present invention relates to a method for the synthesis of a halo olefin of formula (I) wherein Hal, R1, R2, R3, R4, X and Y are defined as hereinbefore or hereinafter, or a salt thereof comprising the step (S1) (S1): protodecarboxylation of an α-halo-acrylic acid derivative of formula (II) Likewise, in an analogous fashion, the invention relates to the synthesis of the E/Z isomer of (I) from the corresponding E/Z isomer of (II). In order to facilitate the following description, only the synthesis of compound (I) as depicted above will be described in detail. This is, however, not to be construed as a limitation of the scope of the invention. In particular, the invention is to provide a process which is carried out under relatively mild and catalytic conditions. In this aspect, it is found that the protodecarboxylation of an α-acrylic acid derivative can be effected in a stereospecific manner in the presence of catalytic amounts of the transition metals copper and/or silver. The results of the respective investigations are presented in section Examples and Experimental Data and are summarized in the following: For the protodecarboxylation step, best results in terms of catalytic activity, e.g. high conversions at low catalyst loadings, short reaction times and few limitations with regard to solvent selection, are obtained in the presence of silver(I). Both silver(I) oxides and salts may be employed as highly efficient catalysts, in particular silver(I) oxide, silver(I) acetate, silver(I) nitrate and silver(I) carbonate, delivering halo olefins in high yields and purities. Good results are also obtained with copper(I), employed in the form of its oxides and/or salts, also in complexes with monodentate ligands, as catalysts for the protodecarboxylation. Non-limiting examples are copper(I) oxide, copper(I) acetate and copper(I) thiophene-2-carboxylate (CuTc). The reaction may also proceed in the presence of copper(II). Catalytically active copper(I) and silver(I) species may also be formed in situ from other oxidation states. Thus, according to one embodiment of the first aspect of the present invention, the protodecarboxylation of an α-acrylic acid derivative is performed in the presence of copper and/or silver. Preferably, copper and/or silver are employed as copper(I) oxide, copper(I) salts, silver(I) oxide and/or silver(I) salts. More preferably, silver(I) oxide or silver(I) salts are used, even more preferably silver(I) acetate and/or nitrate and/or carbonate, most preferably silver(I) acetate and/or silver(I) nitrate. Advantageously, copper and/or silver may be employed in substoichiometric amounts in order for the protodecarboxylation to proceed rapidly to full conversion. Catalyst loadings of and below mol % (“mol %” designating the amount of the catalytically active copper and/or silver atoms in relation to the molecules of the compound of formula (II)) are used very successfully. It is also found that, e.g. by adjusting the solvent volume and reaction temperature and depending on the reaction conditions, the catalyst loading may be decreased even further, at least down to the low single-digit mol % range. The actually optimum catalytic amount will of course depend on factors known to those skilled in the art such as structural features of the starting materials, further reaction conditions and parameters, acceptable reaction times and potential side reactions. Thus, according to another embodiment, copper and/or silver in the protodecarboxylation are employed in catalytic amounts, i.e. in amounts of not more than 50 mol %, e.g. in the range from 2.5 mol % to 50 mol %, preferably of not more than 20 mol %, more preferably of not more than mol %, most preferably of not more than 7.5 mol %. Preferred lower limits of the catalytic range may be 7.5 mol %, 5 mol %, 2.5 mol % or 1 mol %. Most preferably, the range is from 5 mol % to mol %. The protodecarboxylation according to the present invention is advantageously carried out in dipolar aprotic solvents: For example, N-methylpyrrolidinone (NMP), N,N-dimethylacetamide (DMAC), pyridine and/or acetonitrile can be applied successfully. Working under anhydrous conditions and protection from oxygen and light are beneficial for the catalyst performance and reaction outcome. Thus, according to another embodiment, the protodecarboxylation is carried out in a medium that comprises one or more dipolar aprotic solvents, preferably selected from the group consisting of acetonitrile, N,N-dimethylacetamide, pyridine or NMP, most preferably NMP. The protodecarboxylation according to the present invention may be carried out without the need for excessive heating. Temperatures below 150° C. are sufficient for the reaction to proceed, most preferably in the range of 120-130° C. Full conversion can be achieved also at significantly lower temperatures, e.g. below 100° C., which may advantageously be made use of for temperature sensitive compounds unless potentially longer conversion times are unacceptable. The actually optimum reaction temperature will of course depend on factors known to those skilled in the art such as structural features of the starting materials, further reaction conditions and parameters, acceptable reaction times and potential side reactions. Thus, according to another embodiment, the protodecarboxylation is conducted at temperatures of not more than 150° C., preferably of not more than 140° C., most preferably of not more than 130° C., e.g. at about 130° C., about 120° C., about 100° C. or about 80° C. Most preferably, the temperature range is from 120° C. to 140° C. Optionally, step (S1) may comprise measures and steps, known to the one skilled in the art, of adding, removing or manipulating protection groups in compounds of formula (II) and/or (I). Such measures and steps may be considered necessary by the one skilled in the art depending on the meaning of the substituents, in particular X and Y, e.g. in order to avoid side reactions. Optionally, step (S1) may comprise measures and steps, known to the one skilled in the art, of transforming the compound of formula (I) into a salt thereof, preferably into a pharmaceutically acceptable salt, most preferably into a hydrochloride salt. Such measures and steps may be considered suitable by the one skilled in the art depending on the meaning of the substituents, in particular Y, e.g. in order to improve the physical and/or chemical properties of compound (I), in particular in order to obtain the compound of formula (I) in an advantageous solid, e.g. crystalline, form that is suitable for the use in pharmaceutical development. For instance, a preferred solid form of compound (I-k) is “Form I”, a crystalline, high-melting, stable form of (I-k) that is not prone to polymorphic conversions. Form I is found to contain water: The molar ratio of (I-k) relative to H2O is in the range from 3:1 to 5:1, more specifically it is 4:1; Form I could therefore be considered to be a tetartohydrate. The X-ray powder diffraction (XRPD) peaks of Form I are given in section Examples and Experimental Data. Hence, in particular, Form I is characterized by an XRPD pattern comprising robin82@example.net, 7.63, 13.55 and 15.29 degrees 2θ, specifically comprising robin82@example.net, 7.63, 13.55, 15.29, 16.03 and 17.80 degrees 2θ, more specifically comprising robin82@example.net, 7.63, 11.46, 13.55, 15.29, 16.03, 17.80 and 19.02 degrees 2θ, even more specifically comprising robin82@example.net, 7.63, 11.46, 13.55, 15.29, 16.03, 17.80, 19.02 19.69, 20.80, 22.64, 23.03, 23.63, 26.93, 27.30 and 27.79 degrees 2θ (for all peaks mentioned above: ±0.2 degrees 2θ, using CuKα1 radiation), even more specifically comprising peaks at degrees 2θ as contained in section Examples and Experimental Data (paragraph (7)) or as shown in FIG. 1 of the present application. Form I is furthermore characterized by a melting point of about 181° C.±5° C. (determined via differential scanning calorimetry (DSC); evaluated as onset-temperature; heating rate 10° C./min). The DSC curve of Form I is depicted in FIG. 3. In addition, characteristic solid-state nuclear magnetic resonance (ssNMR) data for Form I is presented in terms of 13C and 19F chemical shifts in section Examples and Experimental Data. Hence, in particular, Form I is characterized by a 13C spectrum comprising robin82@example.net, 162.5 and 167.9 ppm, specifically comprising robin82@example.net, 149.0, 151.4, 154.0, 156.6, 161.1, 162.5 and 167.9 ppm, more specifically comprising robin82@example.net, 129.2, 130.1, 131.3, 148.4, 149.0, 151.4, 154.0, 156.6, 161.1, 162.5 and 167.9 ppm, even more specifically comprising robin82@example.net, 29.9, 128.3, 129.2, 130.1, 131.3, 148.4, 149.0, 151.4, 154.0, 156.6, 161.1, 162.5 and 167.9 ppm (for all peaks mentioned above: ±0.2 ppm), even more specifically comprising peaks as contained in section Examples and Experimental Data (paragraph (9)) or as shown in FIG. 4 of the present application. Also, Form I is characterized by a 19F chemical shift of −115.1 ppm (±0.2 ppm). Form I of (I-k) may be obtained from compound (I-j′) by a method comprising the following steps: (a) addition of at least one molar equivalent of HCl to a solution of (I-j′), (b) optionally effecting and/or supporting precipitation of (I-k), (c) allowing crystallization of (I-k), (d) optional isolation of the precipitate of steps (a) and/or (b) and/or (c), (e) optional recrystallization of the precipitate of steps (a) and/or (b) and/or (c) and/or (d), (f) isolation of Form I of (I-k). In step (a), the mentioned solution may be prepared by dissolving (I-j′) in any form obtainable, in particular in solid form, e.g. crystalline or amorphous, in a solvent or solvent mixture as described below. As an alternative, step (a) may directly adjoin the synthesis of (I-j′), i.e. without isolation or purification of (I-j′). For example, the mentioned solution may be prepared by dilution of a concentrated solution of (I-j′) which was obtained by workup of the reaction mixture in which (I-j′) had been formed, e.g. according to WO 501.761.4010 or the present application. Preferably the solution of (I-j′) prepared in step (a) is a saturated or nearly saturated solution at the given temperature. The terms “saturated” or “nearly saturated” are related to the starting material of (I-j′) as used in step (a). In particular, the concentration of (I-j′) in the solution of step (a) may be in the range from about 150 mmol/L to about 600 mmol/L, e.g. about 175 mmol/L, about 270 mmol/L, about 315 mmol/L, about 370 mmol/L or about 500 mmol/L. The solution of (I-j′) used for step (a) preferably comprises at least two different solvents in order to provide both sufficient solubility for (I-j′) and the desired crystallization properties for (I-k) in later steps of the process. Therefore, the medium comprises at least one protic solvent, preferably selected from alcohols, more preferably from ethanol and isopropyl alcohol, most preferably isopropyl alcohol. Also, the medium preferably comprises at least one aprotic solvent, preferably selected from alkanes, aromatic solvents, ethers and esters, more preferably from heptane, toluene, 2-methyl-tetrahydrofuran (2-Me-THF), methyl tert-butyl ether (MTBE) and ethyl acetate, most preferably from heptane, toluene and ethyl acetate. In particular, the medium may consist of two different solvents one of which is a protic solvent. One preferred solvent mixture is isopropyl alcohol/ethyl acetate wherein the volume ratio of isopropyl alcohol and ethyl acetate is in the range from about 1:1 to 1:3, e.g. the volume ratio is about 1:2. Also, the medium may in particular consist of three different solvents one of which is a protic solvent. One preferred solvent mixture is isopropyl alcohol/heptane/toluene wherein the volume ratio of isopropyl alcohol and heptane is in the range from about 1:1 to about 1:1.5 and wherein the volume ratio of isopropyl alcohol and toluene is in the range from about 1:3 to about 1:5, e.g. the volume ratio of the three components is about 1:1.2:3.4. Another preferred solvent mixture is isopropyl alcohol/2-Me-THF/ethyl acetate wherein the volume ratio of isopropyl alcohol and 2-Me-THF is in the range from about 1:0.3 to about 1:1 and wherein the volume ratio of isopropyl alcohol and ethyl acetate is in the range from about 1:1 to about 1:2, e.g. the volume ratio of the three components is about 1:0.5:1.2, about 1:0.4:1.3, about 1:0.6:1.5 or about 1:0.5:1.8. The solution may be heated up to the boiling temperature of the solvent mixture or to a temperature in the range from about 65° C. to about 80° C., e.g. to about 68° C., to about 70° C. or to about 75° C. The solution may be filtered, e.g. over charcoal. In step (a), HCl is preferably added as a solution, e.g. in isopropyl alcohol at concentrations of about 5-6 mol/L or in diethyl ether at concentrations of about 1-2 mol/L. For full conversion of (I-j′) to (I-k), at least 1.0 molar equivalents (eq) of HCl are to be added, preferably from 1.0 to 1.5 eq, e.g. about 1.2 eq. The temperature during addition of HCl may be room temperature, i.e. about 20-30° C., e.g. about 25° C., or about 60-75° C., e.g. about 68° C., depending, among others, on the solvent system used. In optional step (b), measures may be taken in order to effect and/or support the precipitation of (I-k), e.g. to facilitate nucleation. Such methods are well known to the one skilled in the art and comprise, but are not limited to the addition of seed crystals, cooling, solvent evaporation, addition of antisolvents and mechanical intervention, e.g. scratching or rubbing. Preferably, seed crystals of (I-k) are added to the solution obtained in step (a), optionally after a filtration step. The mass of the seed crystals relative to the total mass of (I-k) may be in the range up to about 5%, more preferably from about 0.001% to 1%. The seed crystals are preferably added at a temperature in the range from about 50° C. to 80° C., most preferably about 60 to 75° C., e.g. at 68° C. In step (c), measures may be taken to allow the crystallization to proceed, preferably to completeness, e.g. to allow further crystal growth. Such methods are well known to the one skilled in the art and comprise, but are not limited to cooling, letting the suspension rest optionally while stirring, and addition of further solvents, in particular to reduce the solubility of the solute, e.g. addition of an antisolvent. Preferably MTBE is added, e.g. about twice the total volume of isopropyl alcohol used in step (a). Preferably, the temperature is lowered to room temperature, if applicable, in order to obtain a high yield of the precipitated form of (I-k). The duration of step (c) may be in the range from about 3 hours to about 12 hours during which stirring should preferably be applied. As known to the one skilled in the art, the size, shape and quality of the obtained crystals can be varied by the period of time and the difference of temperature in step (c). In optional steps (d) and (e), the crystals formed in steps (b) and/or (c) may be isolated and recrystallized in order to improve the purity and quality of the crystals. The techniques used in these steps are well known to the ones skilled in the art. Methods for isolation are detailed below for step (f). Recrystallization according to step (e) may advantageously be performed using solvent systems that correspond to the ones described in or resulting from steps (a) to (c). Thus, the solvent system comprises at least one protic solvent and at least one aprotic solvent. Preferably the one or more protic solvents are selected from water and alcohols, more preferably from water, methanol, ethanol and isopropyl alcohol, most preferably it is isopropyl alcohol. The one or more aprotic solvents are preferably selected from alkanes, ketones, ethers and esters, more preferably from heptane, acetone, 2-methyl-tetrahydrofuran (2-Me-THF), methyl tert-butyl ether (MTBE), isopropyl acetate and ethyl acetate, most preferably from MTBE and ethyl acetate. Preferred solvent systems are selected from the group consisting of water/ethanol/ethyl acetate, water/isopropyl alcohol/ethyl acetate, isopropyl alcohol/ethyl acetate/MTBE, methanol/ethyl acetate, water/isopropyl acetate/acetone and water/isopropyl alcohol/heptane, preferably selected from water/ethanol/ethyl acetate, water/isopropyl alcohol/ethyl acetate and isopropyl alcohol/ethyl acetate/MTBE; more preferably the solvent system is isopropyl alcohol/ethyl acetate/MTBE wherein the volume ratio of isopropyl alcohol and ethyl acetate is in the range from about 1:1 to about 1:0.75 and wherein the volume ratio of isopropyl alcohol and MTBE is in the range from about 1:0.9 to about 1:0.65, e.g. the volume ratio of the three components is 9:8:7. In step (f), Form I of (I-k) is isolated from solution by means known to the one skilled in the art which comprise, but are not limited to centrifugation and filtration. In particular, step (f) comprises filtration, washing of the filter cake and drying under vacuum. The obtained crystals are preferably washed with a solvent or a mixture of solvents, wherein the solvent is preferably selected from MTBE and a 3:1 (v/v) mixture of heptane/isopropyl alcohol followed by heptane. The most preferred solvent is MTBE. Preferably, remaining solvent(s) are advantageously removed from the crystals in a drying step under vacuum, for example at about 60° C. for about 5 to 12 hours. The temperature, the pressure and the duration of this drying step may be chosen in order to lower the content of one or more residual solvents below a given value. Alternatively, Form I of (I-k) may be obtained from “Form II”, an anhydrous form of (I-k). Form II is obtainable by excessive drying of (I-k) or from a solution of (I-k) by evaporation of the solvent, e.g. from a solution of (I-k) in acetone upon slow evaporation of the solvent at ambient conditions or from a 50 mg/mL solution of (I-k) in methanol upon fast evaporation of the solvent, i.e. over 15 minutes at 60° C. under vacuum, preferably with dry nitrogen or dry air as vacuum oven vent gas. Form I may be obtained from Form II by recrystallization according to techniques described herein or known to the ones skilled in the art, e.g. from water/ethanol/ethyl acetate, water/isopropyl alcohol/ethyl acetate, isopropyl alcohol/ethyl acetate/MTBE, methanol/ethyl acetate, water/isopropyl acetate/acetone and water/isopropyl alcohol/heptane, heptane, ethyl acetate, isopropyl acetate, isopropyl alcohol, anisole, methyl ethyl ketone, α,α,α-trifluoro toluene and mixtures thereof, preferably from heptane, ethyl acetate, isopropyl acetate, anisole, ethyl acetate/isopropyl alcohol 1:1 and α,α,α-trifluoro toluene/methyl ethyl ketone 1:1. In addition, the recrystallization procedure as disclosed above in step (e) may be employed. Also, Form I may be obtained by reconditioning of Form II, i.e. by exposing Form II to relative humidities of not less than 15%. Differentiation between Form I and Form II and hence monitoring of the completeness of the conversion may be achieved by collecting X-ray powder diffraction (XRPD) and/or differential scanning calorimetry (DSC) and/or solid-state nuclear magnetic resonance (ssNMR) data as far as they are characteristic for the different crystalline forms. As a further alternative, Form I of (I-k) may be formed from ethanol solvates of (I-k). Ethanol solvates of (I-k), in particular in a 1:1 molar ratio, can be recovered from ethanol and ethanol/heptane solvent systems, e.g. of volume ratios of ethanol:heptane of 2:1, 1:1, and 1:2, preferably from ethanol or ethanol/heptane 1:1, upon evaporation at room temperature. Form I may be obtained from ethanol solvates by recrystallization according to techniques described herein or known to the ones skilled in the art, e.g. from water/ethanol/ethyl acetate, water/isopropyl alcohol/ethyl acetate, isopropyl alcohol/ethyl acetate/MTBE, methanol/ethyl acetate, water/isopropyl acetate/acetone and water/isopropyl alcohol/heptane, heptane, ethyl acetate, isopropyl acetate, isopropyl alcohol, anisole, methyl ethyl ketone, α,α,α-trifluoro toluene and mixtures thereof, preferably from heptane, ethyl acetate, isopropyl acetate, anisole, ethyl acetate/isopropyl alcohol 1:1 and α,α,α-trifluoro toluene/methyl ethyl ketone 1:1. In addition, the recrystallization procedure as disclosed above in step (e) may be employed. Also, Form I may be obtained from ethanol solvates of (I-k) by desolvation upon drying at ambient conditions or heating to temperatures in the range from about 75° C. to about 110° C. The present invention also provides a method for the synthesis of a halo olefin of formula (I) wherein Hal, R1, R2, R3, R4, X and Y are defined as hereinbefore or hereinafter comprising the steps (S2): formation of an α-halo-acrylic acid derivative of formula (II) from ketone (III) and (S1) as defined hereinbefore or hereinafter In particular, a method for the stereoselective conversion from a ketone of formula (III) to a halo olefin of formula (I) is provided. Previous approaches for the terminal halo olefin (I) formation from ketones (III) have typically proceeded via Wittig reactions which often deliver poor E/Z selectivities and therefore necessitate further potentially cumbersome separation steps and impact the overall reaction yield (van Steenis et al., J. Chem. Soc., Perkin Trans. 1, 2002, 2117-2133; Landelle et al., Chem. Soc. Rev. 2011, 40, 2867-2908). The protodecarboxylation (S1) of the present invention, in contrast, paves the way for said conversion from (III) to (I) to be performed via α-halo-acrylic acid derivatives of formula (II). Compounds of formula (II) are readily accessible from ketones (III) by the Horner-Wadsworth-Emmons reaction which may, with the proper choice of the base, deliver improved E/Z selectivities in comparison to Wittig olefinations. This improved selectivity is maintained in the stereospecific protodecarboxylation of (II) to form olefin (I). Overall, the incorporation of the protodecarboxylation into said conversion from (III) to (I) thus allows for obtaining improved E/Z selectivities, installed in the formation of (II) (step (S2)) and maintained in its protodecarboxylation (step (S1)). This more favorable isomeric purity in turn may help to simplify or avoid further isomeric separation e.g. by crystallization or chromatography, and to improve the reaction yield. Also, in this reaction sequence, the option is provided to perform isomeric separation—additionally or only—on the stage of the intermediate (II), which, depending on the particular circumstances, may be more effective and/or efficient than on the stage of the product (I). Step (S2) is explained in more detail in the following: The α-halo-acrylic acid derivative of formula (II′) can in principle be formed from ketones (III) via Horner-Wadsworth-Emmons protocols known in the art (e.g. Maryanoff et al., Chem. Rev. 1989, 89, 863-927; Al Jasem et al., J. Chem. Res. 2014, 38, 453-463; Sano et al., Tetrahedron Letters 2014, 55, 6248-6251), e.g. by using phosphonates of formula (IV) as reagents in the presence of basic additives: wherein Hal, R, R0, R1, R2, R3, R4, X and Y are defined as hereinbefore or hereinafter. In case R0 is not H, (S2) preferably also comprises the saponification of the acrylic acid ester (II′) to the acrylic acid (II), for instance saponification in situ, according to procedures known to the one skilled in the art. The saponification may be performed either prior to or after separation and/or isolation of the E/Z isomers. The formation of the acrylic acid by saponification may also be beneficial for the separation of the E and Z isomers either by chromatographic methods or by crystallization. An example of a synthesis according to the step (S2) is: It is found for the conversion of (III) to (II) in the presence of (IV), in particular from (III-j) to (II-j) in the presence of (IV-a), that good to very good reaction yields can be obtained with a number of different bases, e.g. n-BuLi, NaHMDS, NaH, t-BuONa, t-BuOK, (t-BuO)2Mg and n-Bu2Mg. However, best results in terms of E/Z ratio of the product are observed when organomagnesium halides, such as MeMgCl, MeMgBr, MeMgI, EtMgBr and i-PrMgCl, are used as bases. Preferably, organomagnesium bromides or iodides, such as MeMgBr, MeMgI and EtMgBr, are used. Thus, according to one embodiment, the method for the synthesis of a halo olefin of formula (I) comprises the steps (S2) and (S1): (S2): reacting a ketone of formula (III) with a phosphonate of formula (IV) in the presence of at least one basic additive, preferably an organomagnesium halide, more preferably C1-4-alkyl magnesium chloride or C1-4-alkyl magnesium bromide, for example MeMgBr, MeMgCl, EtMgBr or i-PrMgCl, most preferably EtMgBr; and saponification of the acrylic acid ester of formula (II′) (in case R0 is not H), and (S1): the protodecarboxylation of the α-halo-acrylic acid derivative of formula (II), carried out in the presence of a catalytic amount of copper and/or silver. In addition, (S2) may optionally comprise measures and steps, known to the one skilled in the art, for the separation of the E and Z isomers to improve the purity of the product, for example, chromatographic methods or crystallization. For instance, the E/Z separation may be performed by crystallization of compound (II), e.g. after the saponification of (II′) to (II). Thus, according to another embodiment, (S2) additionally comprises the E/Z purification of the compound of formula (II). According to another embodiment, the halo olefin of formula (I) is formed from ketone (III) with an E/Z selectivity of not less than 80:20, preferably not less than 90:10, most preferably not less than 95:5 via the steps (S2), comprising saponification in case R0 is not H and optionally comprising E/Z purification, and (S1). According to another embodiment, (S2) is carried out at temperatures in the range from −20° C. to 70° C., preferably in the range from −10° C. to 40° C. According to another embodiment, (S2) is carried out in an aprotic medium, preferably selected from the group consisting of tetrahydrofuran (THF), 2-methyl-THF, dimethylsulfoxide (DMSO), dimethylether (DME), toluene (PhMe) and mixtures thereof, preferably in THF, 2-methyl-THF and mixtures thereof. According to another embodiment, the compound of formula (IV) in (S2) is employed in amounts of 1 to 2.5 equivalents in relation to compound (III), preferably in an amount of 1.1 to 1.5 equivalents, most preferably in an amount of about 1.2 equivalents. Optionally, step (S2) may comprise measures and steps, known to the one skilled in the art, of adding, removing or manipulating protection groups in compounds of formula (III) and/or (II). Such measures and steps may be considered necessary by the one skilled in the art depending on the meaning of the substituents, in particular X and Y, e.g. in order to avoid side reactions. In the processes according to this invention, the following meanings of groups, residues and substituents are preferred. Any and each of the above and below definitions of the groups, residues and substituents may be combined with each other: According to one embodiment, Hal is selected from the group Hal-G1 consisting of F, Cl, Br and I. According to another embodiment, Hal is selected from the group Hal-G2 consisting of F and Cl. According to another embodiment, Hal is selected from the group Hal-G3 consisting of F. According to another embodiment, R1, R2, R3 and R4 are independently selected from the group Ri-G1 consisting of H, halogen, CN, substituted or unsubstituted C1-10-alkyl, substituted or unsubstituted C3-10-cycloalkyl, substituted or unsubstituted C2-10-alkenyl, substituted or unsubstituted C2-10-alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted aryl-C16-alkylene-, substituted or unsubstituted heteroaryl and substituted or unsubstituted heteroaryl-C1-6-alkylene-. According to another embodiment, R1, R2, R3 and R4 are independently selected from the group Ri-G2 consisting of H, halogen, CN, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl and cyclopropyl, wherein said methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl and cyclopropyl may be partially or fully halogenated, preferably fluorinated. According to another embodiment, R1, R2, R3 and R4 are independently selected from the group Ri-G3 consisting of H, halogen, CN and methyl, wherein said methyl may be partially or fully halogenated, preferably fluorinated. According to another embodiment, R1, R2, R3 and R4 are independently selected from the group Ri-G4 consisting of H. According to another embodiment, X is selected from the group X-G1 consisting of R1, ORX, SRX, S(O)RX, SO2RX, NRY1RY2, N(O)RY1RY2, PRY1RY2 and P(O)RY1RY2, wherein R1, RX, RY1 and RY2 are defined as hereinbefore or hereinafter. According to another embodiment, X is selected from the group X-G2 consisting of ORX, SRX, S(O)RX and SO2RX, wherein RX is defined as hereinbefore or hereinafter. According to another embodiment, X is selected from the group X-G3 consisting of ORX, wherein RX is defined as hereinbefore or hereinafter. According to another embodiment, Ri is selected from the group Ri-G1 as defined hereinbefore. According to another embodiment, Ri is selected from the group Ri-G2 as defined hereinbefore. According to another embodiment, Ri is selected from the group Ri-G3 as defined hereinbefore. According to another embodiment, Ri is selected from the group Ri-G4 as defined hereinbefore. According to another embodiment, RX is selected from the group RX-G1 consisting of Ri as defined hereinbefore or hereinafter. According to another embodiment, RX is selected from the group RX-G2 consisting of H, substituted or unsubstituted C1-10-alkyl, substituted or unsubstituted C3-10-cycloalkyl, substituted or unsubstituted C2-10-alkenyl, substituted or unsubstituted C2-10-alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted aryl-C1-6-alkylene-, substituted or unsubstituted heteroaryl and substituted or unsubstituted heteroaryl-C1-6-alkylene-. According to another embodiment, RX is selected from the group RX-G3 consisting of aryl and heteroaryl, all of which substituted with Rar, wherein Rar is defined as hereinbefore or hereinafter. According to another embodiment, RX is selected from the group RX-G4 consisting of phenyl, substituted with Ra wherein Rar is defined as hereinbefore or hereinafter. According to another embodiment, Rar is selected from the group Rar-G1 consisting of C(O)NRN1RN2 and SO2NRN1RN2, wherein RN1 and RN2 are defined as hereinbefore or hereinafter. According to another embodiment, Rar is selected from the group Rar-G2 consisting of C(O)NRN1RN2, wherein RN1 and RN2 are defined as hereinbefore or hereinafter. According to another embodiment, Rar is selected from the group Rar-G3 consisting of C(O)NHt-Bu. According to another embodiment, RN1 and RN2 are independently selected from the group RN-G1 consisting of H, substituted or unsubstituted C1-6-alkyl and substituted or unsubstituted C3-7-cycloalkyl. According to another embodiment, RN1 and RN2 are independently selected from the group RN-G2 consisting of H and substituted or unsubstituted methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl and tert-butyl. According to another embodiment, RN1 and RN2 are independently selected from the group RN-G3 consisting of H and tert-butyl. According to another embodiment, Y is selected from the group Y-G1 consisting of Ri, ORX, SRX, S(O)RX, SO2RX, NRY1RY2, N(O)RY1RY2, PRY1RY2 and P(O)RY1RY2, wherein Ri, RX, RY1 and RY2 are defined as hereinbefore or hereinafter. According to another embodiment, Y is selected from the group Y-G2 consisting of NRY1RY2, PRY1R2 and P(O)RY1RY2, wherein RY1 and RY2 are defined as hereinbefore or hereinafter. According to another embodiment, Y is selected from the group Y-G3 consisting of NRY1RY2, wherein RY1 and RY2 are defined as hereinbefore or hereinafter. According to another embodiment, Y is selected from the group Y-G4 consisting of NRY1RY2, wherein RY1 and RY2 are defined as hereinbefore or hereinafter. According to another embodiment, RY1 and RY2 are independently selected from the group RY-G1a consisting of Ri, C(O)Ri and C(O)ORi, wherein Ri is defined as hereinbefore, or RY1 and RY2 are selected from the group RY-G1b in which RY1 and RY2 are linked to form, together with N or P to which they are attached, substituted or unsubstituted heteroaryl or substituted or unsubstituted heterocyclyl. According to another embodiment, RY1 and RY2 are independently selected from the group RY-G2a consisting of H, substituted or unsubstituted C1-10-alkyl, substituted or unsubstituted C3-10-cycloalkyl, substituted or unsubstituted C2-10-alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted aryl-C1-6-alkylene-, substituted or unsubstituted C1-10-alkyl-C(O)—, substituted or unsubstituted aryl-C(O)—, substituted or unsubstituted aryl-C1-6-alkylene-C(O)—, substituted or unsubstituted C1-10-alkyl-OC(O)—, substituted or unsubstituted aryl-OC(O)— and substituted or unsubstituted aryl-C1-6-alkylene-OC(O)— or RY1 and RY2 are selected from the group RY-G2b in which RY1 and RY2 are linked to form, together with N or P to which they are attached, substituted or unsubstituted heteroaryl or substituted or unsubstituted heterocyclyl. According to another embodiment, RY1 and RY2 are independently selected from the group RY-G3a consisting of H, substituted or unsubstituted C1-6-alkyl, substituted or unsubstituted C2-6-alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted aryl-C1-4-alkylene-, substituted or unsubstituted C1-6-alkyl-C(O)—, substituted or unsubstituted aryl-C(O)—, substituted or unsubstituted aryl-C1-4-alkylene-C(O)—, substituted or unsubstituted C1-6-alkyl-OC(O)—, substituted or unsubstituted aryl-OC(O)— and substituted or unsubstituted aryl-C1-4-alkylene-OC(O)— or RY1 and RY2 are selected from the group RY-G3b in which RY1 and RY2 are linked to form, together with N or P to which they are attached, substituted or unsubstituted heteroaryl or substituted or unsubstituted heterocyclyl. According to another embodiment, RY1 and RY2 are independently selected from the group RY-G4a consisting of H, substituted or unsubstituted Ac (acetyl), substituted or unsubstituted Boc (tert-butyloxycarbonyl), substituted or unsubstituted Cbz (carboxybenzyl), substituted or unsubstituted Fmoc (fluorenylmethyloxycarbonyl), substituted or unsubstituted Alloc (allyloxycarbonyl), substituted or unsubstituted t-Bu (tert-butyl), substituted or unsubstituted Bn (benzyl) and substituted or unsubstituted phthaloyl or RY1 and RY2 are selected from the group RY-G4b in which RY1 and RY2 are linked to form, together with N to which they are attached, substituted or unsubstituted phthalimide or substituted or unsubstituted pyrrole. According to another embodiment, RY1 and RY2 are independently selected from the group RY-G5a consisting of H and substituted or unsubstituted phthaloyl or RY1 and RY2 are selected from the group RY-G5b in which RY1 and RY2 are linked to form, together with N to which they are attached, substituted or unsubstituted phthalimide. According to another embodiment, RY1 and RY2 are independently selected from the group RY-G6 consisting of H. Further subgeneric embodiments of the compounds of formula (I) are set forth as embodiments (I-a) to (I-f) in the following table, wherein the above-mentioned substituent definitions are used (R1, R2, R3 and R4 as well as RN1 and RN2 are meant to be selected independently from the given group; RY1 and RY2 are meant to be selected independently from the given subgroup designated with “a” or selected from the given subgroup designated with “b”): Substituents R1, R2, RN1, Embodiment Hal R3, R4 X RX Rar RN2 Y RY1, RY2 (I-a) Hal-G2 Ri-G2 X-G2 RX-G2 Rar-G1 RN-G1 Y-G3 RY-G4a or RY-G4b (I-b) Hal-G2 Ri-G3 X-G3 RX-G3 Rar-G1 RN-G2 Y-G4 RY-G4a or RY-G4b (I-c) Hal-G2 Ri-G3 X-G3 RX-G4 Rar-G1 RN-G2 Y-G4 RY-G5a or RY-G4b (I-d) Hal-G2 Ri-G3 X-G3 RX-G4 Rar-G2 RN-G2 Y-G4 RY-G5a or RY-G5b (I-e) Hal-G3 Ri-G3 X-G3 RX-G4 Rar-G2 RN-G2 Y-G4 RY-G5a or RY-G5b (I-f) Hal-G3 Ri-G4 X-G3 RX-G4 Rar-G2 RN-G2 Y-G4 RY-G5a or RY-G5b According to one embodiment, in step (S1), the compound of formula (II) is compound (II-g) wherein Rar as well as RY1 and RY2 are defined as hereinbefore or hereinafter, preferably Rar is selected from the group Rar-G1 as defined hereinbefore, more preferably from the group Rar-G2 as defined hereinbefore, wherein RN1 and RN2 are preferably independently selected from the group RN-G2 as defined hereinbefore, more preferably from the group RN-G3 as defined hereinbefore, and preferably RY1 and RY2 are independently selected from the group RY-G4a as defined hereinbefore or are selected from the group RY-G4b as defined hereinbefore, more preferably independently selected from the group RY-G5a as defined hereinbefore or are selected from the group RY-G5b as defined hereinbefore, and the compound of formula (I) is compound (I-g) wherein Rar as well as RY1 and RY2 are defined as hereinbefore. According to another embodiment, in step (S1), the compound of formula (II) is compound (II-h) wherein Rar is selected from the group Rar-G2 as defined hereinbefore in connection with RN-G2 as defined hereinbefore, and the compound of formula (I) is compound (I-h) wherein Rar is defined as hereinbefore. According to another embodiment, in step (S1), the compound of formula (II) is compound (II-i) wherein RY1 and RY2 are independently selected from the group RY-G4a as defined hereinbefore or are selected from the group RY-G4b as defined hereinbefore, and the compound of formula (I) is compound (I-i) wherein RY1 and RY2 are defined as hereinbefore. According to another embodiment, in step (S1), the compound of formula (II) is compound (II-j) and the compound of formula (I) is compound (I-j) According to one embodiment, step (S1) comprises the deprotection of compound (I-g) wherein Rar as well as RY1 and RY2 are defined as hereinbefore or hereinafter, preferably Rar is selected from the group Rar-G1 as defined hereinbefore, more preferably from the group Rar-G2 as defined hereinbefore, wherein RN1 and RN2 are preferably independently selected from the group RN-G2 as defined hereinbefore, more preferably from the group RN-G3 as defined hereinbefore, and preferably RY1 and RY2 are independently selected from the group RY-G4a as defined hereinbefore or are selected from the group RY-G4b as defined hereinbefore, more preferably independently selected from the group RY-G5a as defined hereinbefore or are selected from the group RY-G5b as defined hereinbefore, to compound (I-g′) wherein Rar is defined as hereinbefore. According to another embodiment, step (S1) comprises the deprotection of compound (I-h) wherein Rar is selected from the group Rar-G2 as defined hereinbefore in connection with RN-G2 as defined hereinbefore, to compound (I-h′) wherein Rar is defined as hereinbefore. According to another embodiment, step (S1) comprises the deprotection of compound (I-i) wherein RY1 and RY2 are independently selected from the group RY-G4a as defined hereinbefore or are selected from the group RY-G4b as defined hereinbefore, to compound (I-j′) According to another embodiment, step (S1) comprises the deprotection of compound (I-j) to compound (I-j′) According to another embodiment, step (S1) comprises the conversion of compound (I-j′) to compound (I-k) According to another embodiment, compound (I-k) is obtained as Form I. Preferred substituents of the compound of formula (IV) wherein Hal is defined as hereinbefore or hereinafter, in step (S2) are as follows: According to one embodiment, R is selected from the group R-G1 consisting of H, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl and phenyl, wherein said methyl, ethyl, n-propyl,
{'bibliographic_information': "{'country': 'US', 'doc-number': '16837008', 'kind': 'B2', 'date': '20200401', 'invention_title': 'Transition metal-catalyzed protodecarboxylation of α-halo-acrylic acid derivatives'}", 'source_file': './grant/2021/ipg210629.xml', 'source_data': 'USPTO-Grant'}