Sequential Asymmetric Catalysis in Michael-Michael-Michael-Aldol Reactions: Merging Organocatalysis with Photoredox Catalysis in a One-Pot Enantioselective Synthesis of Highly Functionalized Decalines Bearing a Quaternary Carbon Stereocenter

An expedited method has been developed for the enantioselective synthesis of highly functionalized decaline systems containing seven contiguous stereogenic centers with high enantioselectivities (>99% ee). The one-pot methodology comprises a cascade of organocatalytic double Michael photocatalyzed Michael aldol reactions of ethyl 2-bromo-6-formylhex-2-enoate, beta-alkyl-alpha,beta-unsaturated aldehydes, and alpha-alkyl-alpha,beta-unsaturated aldehydes. The structure and absolute configuration of an appropriate product were confirmed by X-ray analysis.