The α-functionalization of tertiary amines has attracted much interest in the past and methods involving one-and two-electron oxidation pathway have been reported (Scheme 1). One-electron oxidation of the amine affords a nitrogen-centered radical cation. The oxidation leads to a massive increase of the acidity of the α-C-H bond relative to the starting amine. Rapid deprotonation of the 3 radical cation gives the α-aminoalkyl radical that can be used for a variety of radical processes, such as for instance addition to alkenes leading to C-C bond formation (one-electron pathway). On the other hand, the α-aminoalkyl radical is more easily oxidized than the starting amine and therefore further oxidation to the corresponding iminium ion can take place (two-electron pathway). The iminium intermediate can be used for a variety of useful ionic transformations. As a consequence, the use of stoichiometric oxidants to perform radical reaction via the one-electron pathway is very challenging due to rapid overoxidation of the intermediate α-aminoalkyl radical to the corresponding iminium ion. Scheme 2. Oxidation of trimethylamine: one-vs. two-electron pathways In this context, the single electron oxidation of amines via photoinduced electron transfer has been shown to be a suitable method to suppress this overoxidation. Mariano and co-workers reported in 1992 the photosensitized generation of α-aminoalkyl radicals from easily oxidized α-silyl amines and their subsequent intra-and intermolecular addition to electron-poor olefins. Interestingly, they reported a 6-endo-trig cyclization process (Scheme 3A). Pandey took also advantage of the oxidation of a bis-α-silylamine to generate an azomethine ylide that can be used in 1,3-dipolar cycloaddition. Pandey, Reiser and co-workers and Nishibayashi independently extended this chemistry to photoredox-mediated protocols not only on α-silylated amines but also respectively on N-aryltetrahydroisoquinolines and on cyclic and acyclic amines. Nishibayashi and co-workers reported the formation of bis-alkylated product starting from symmetrical starting materials, demonstrating that the intermediate mono-alkylated product has a similar reactivity as the starting amine under specific reaction conditions (Scheme 3B). In 2014, MacMillan and co-workers reported the α-vinylation of aniline derivatives and N-Boc-protected amino acids using vinyl sulfones as coupling partners (Scheme 3C). In this case, no bis-vinylation was reported presumably due to the excess of the starting amine used under their conditions. The same year, Li and co-workers reported the first α-allylation of N-aryl tertiary amines using an allylic radical trap. Double addition to the radical trap was observed in one case albeit in very moderate yield (Scheme 3D). In 2020, Ready and co-workers reported a method for the regioselective α-functionalization of tertiary amines. Interestingly, the initially formed α-alkylation product could be further alkylated in a one-pot sequence (Scheme 3E). The second alkylation takes place in a regioselective manner at the aliphatic position over the benzylic position. In one example, they observed the formation of a remarkable [3+3] adduct (Scheme 3E). In this reaction, the initial radical adduct is presumably abstracting a hydrogen from the benzylic position. Reduction of the benzylic radical followed by nucleophilic displacement of the Evans auxiliary account for product formation. All these results incited us to examine the approach described in Scheme 3F where α,α'double activation of cyclic tertiary N-arylamines will be used to generate the 1,3-bis radical donors and substituted ester activated allylating agents will be used as a 1,3-bis radical acceptors. The success of this approach will require the ability to meet several challenges such as for instance the control of the regioselectivity of the formation of the second radical and the ability to run a 6-endo-cyclization process leading to a bicyclic framework in competition with intermolecular processes either with the trap or with the monoallylated tertiary amine. Scheme 3. Photoredox catalyzed α-functionalization of tertiary amines. Leading contributions in the field (A-D) and proposed annulation strategy (F). Proof of concept and optimization. To prove the validity of the annulation approach, Nphenylpyrrolidine 1a was reacted in 1,2-dichloroethane with a series of allyl radical traps possessing different leaving groups Y in the presence of different catalysts and base additives. The results are collected in Table (more entries are available in the supporting information). Three side products were identified during this optimization phase: the mono-allylated product 2a (an intermediate in the reaction leading to 3a), the α,α'-bis-allylated product 4a and the bis-addition product 5a. Since all these side products are difficult to separate from the desired tropane 3a, conditions were sought to minimize their formation. We started the optimization by using ethyl 2-((phenylsulfonyl)methyl)acrylate (Y = SO2Ph, 1.2 equivalents) as a trap under conditions similar to the one reported in the literature for reactions with vinyl sulfones (see Scheme 2C), i.e. by using [Ir{dF(CF3)ppy}2(dtbpy)]PF6 (Ir-A) as a catalyst, CsOAc (3 equivalents) as a base and irradiating with 390 nm LEDs in 1,2-dichloroethane (DCE) (Table , entry 1). Gratifyingly, the reaction afforded the desired tropane 3a in 45% yield (all yields determined by 1 H-NMR analysis using an internal standard). Decreasing the base loading to 1.2 equivalents and slightly increasing the amount of the allylsulfone to 1.4 equivalents proved to be beneficial and the product was formed in 65% yield (Table , entry 3). However, under these conditions, the product was contaminated with 4a and 5a leading to difficult isolation (isolated yield of 43%). The readily available catalyst [Ir(dtbbpy)(ppy)2]PF6 (Ir-B) proved to be a suitable catalyst for the reaction, yielding the cyclized product in 47% yield (Table , entry 4). A screening of bases revealed that CsOAc was the optimal base. The use of NaOAc and Cs2CO3 gave low yields of mono-allylated pyrrolidine 2a (Table and). The use of [Ir(dFppy)2(dtbbpy)]PF6 (Ir-C) afforded the cyclic product 3a in 50% yield (Table , entry 7). Other catalysts presenting suitable redox properties were also tested (for redox properties of the tested catalysts, see supporting information). Ru(bpy)3(PF6)2 (Ru-A) and 2,4,5,6-tetrakis(9H-carbazol-9-yl) isophthalonitrile (4CzIPN) afforded the bicycle 3a, together with significant amounts of mono-allylated intermediate 2a (Table , entries 8-9). Eosin Y provide only the mono-allylated product 2a (51% yield, Table , entry 10). The influence of the radical trap was investigated next. Pleasingly, ethyl 2-(acetoxymethyl)acrylate (Y = OAc) gave the desired product in shorter reaction time (Table , entry 11) and similar yield than that with the sulfone trap (Table , entries 3). The corresponding sulfide trap (Y = S-tert-docedyl) provided also the desired cyclized product in satisfactory yield (Table , Entry 12). However, product isolation was more difficult and the release of one equivalent of a smelly thiol makes the reaction less attractive. Finally, the allyl bromide (Y = Br) was tested and only intermediate 2a was obtained, with no further conversion to the tropane skeleton 3a (Table , Entry 13). Other catalysts (organic photocatalysts), bases (Na2CO3, K2CO3) and solvents (DMF, DME, EtOAc, DCM or MeCN) were tested but were all detrimental to the formation of 3a (see supporting information). Due to shorter reaction time and cleaner product formation, the reaction was further optimized using the allyl acetate trap and catalyst Ir-A. The formation of the bis-allylated product 4a and the bis-addition product 5a could be minimized by working under higher dilution (0.05 M) and a much shorter reaction time of 20 minutes (Table , entry 14). Reducing the catalyst loading to 1 mol% proved beneficial to the reaction (Table , entry 15) and using a smaller excess of the allyl acetate radical trap (1.1 equivalents) did not affect the reaction yield (Table ). Finally, the optimized conditions were used with the corresponding pivalate (Y = OPiv) and trifluoroacetate (Y = OTFA) radical traps (Table , entries 17 and 18) but the yields were lower, particularly with the trifluoroacetate.