Rh-Catalyzed Intramolecular Olefin Hydroacylation: Enantioselective Synthesis of Seven- and Eight-Membered Heterocycles

This communication describes the first rhodium-catalyzed intramolecular olefin hydroacylation to produce medium-sized heterocyclic ketones with high regio- and enantiocontrol. Both alpha- and beta-substituted ketones can be produced, depending on catalyst choice and substrate structure. In this stereoselective C-H bond functionalization, ethers, sulfides, and sulfoxides function as effective directing groups. Results from an isotopic labeling study suggest reductive elimination is not the turnover-limiting step in this olefin hydroacylation; thus, the proposed mechanism is distinct from those previously reported.