Unusual DBU-catalyzed decarboxylative formation of allylic thioethers from vinyl cyclic carbonates and thiols

An unanticipated exo-cyclic nucleophilic attack of thiol reagents on vinyl cyclic carbonates is described under DBU catalysis. The process allows the production of allylic thioethers under moderately mild conditions following a sequence of steps that involve a nucleophilic attack of the thiol on the C-terminus of the C=C bond, carbonate ring-opening, and decarboxylation followed by final protonation. This unusual thiol-induced ring-opening complements the previously reported and more widely observed endo-cyclic nucleophilic attack on either the carbonate or methylene carbon centers, and therefore amplifies the reactivity modes that can be accessed with these heterocycles.

Automated summary

An unanticipated exo-cyclic nucleophilic attack of thiol reagents on vinyl cyclic carbonates is described, leading to the synthesis of allylic thioethers. This reaction pathway adds to the reactivity modes available for these heterocycles, complementing the previously reported endo-cyclic nucleophilic attack.