Alkyl sulfones. Having a practical and scalable procedure to reagent 1 in hand, we wondered if other alkyl sulfones could be obtained in a similar way. In fact, treatment of ethyl (61) and isopropyl (62) carboxylic acids (see SI p. 48 and 51) under Vilsmeier-Haack conditions gave the desired reagents 61a, 62a (Scheme 4B). For difluoromethyl-and trifluoromethyl-containing compounds, we discovered that the tert-butyl esters 63 and 64 could be directly converted in one step into the vinamidinium salts 63a, 64a. The reaction of all four reagents 61a-64a with hydrazine hydrate gave pyrazoles 61b-64b in 25-71% yield. The treatment of reagents 61a-64a with guanidine provided pyrimidines 61c-64c in 31-79% yield. These two representative reactions of reagents 61a-64a demonstrated that they could be widely used for the preparation of other sulfonylated derivatives similar to those obtained from reagent 1 (Schemes 3, 4). The molecular structures of compounds 63b, 64a and 64b were confirmed by X-ray crystallographic analysis. Due to the discovery of the Brigatinib drug, the P(O)Me2substituent has recently become popular in chemistry. We, therefore, decided also to attempt the preparation of the corresponding vinamidinium salt (Scheme 4C). Unfortunately, the reaction of carboxylic acid 65 under the previously used conditions led to the formation of a complex mixture, rather than the desired reagent 65a. Scheme 3. Reaction conditions: compounds 31-47 and 49-56: N,N-bis-nucleophiles, Py, 90 °C, 12 h; compound 48: methyl 5-aminofuran-2-carboxylate, K2CO3, MeCN, 60 °C, 12 h. X-ray crystal structures of compounds 34, 41, 42 and 45 (carbonwhite, oxygenred, sulfurgreen, bromineorange, nitrogen -blue). Ellipsoids are shown at 30% probability level. Comparison with other methods. The reagent 1 developed herein can be used not only to make new sulfones, but also to simplify the synthesis of the existing ones. The synthesis of pyrazole 2 was already discussed earlier (Scheme 1). Another example involves pyrimidine 14c, which was reported in a patent. It was obtained in milligram quantities in 7% total yield from bromide 66 (Scheme 4D). Using our method, pyrimidine 14c could be obtained from reagent 1 in 53 g scale in a single run in 65% yield. Analogously, amine 18b was obtained previously in 41% yield from the nitrile 67. Using reagent 1, this product could be obtained in a multigram amount in one run in 88% yield (Scheme 4D). Recently, bicyclo[1.1.1]pentanes were introduced as saturated bioisosteres of the benzene ring. Therefore, novel methods to access these molecules are of importance.