Organocatalytic asymmetric tandem Michael-Henry reactions: A highly stereoselective synthesis of multifunctionalized cyclohexanes with two quaternary stereocenters

摘要

A novel organocatalytic asymmetric tandem Michael-Henry reaction catalyzed by 9-amino-9-deoxyepiquinine (VI) has been developed. The reaction was efficiently catalyzed by catalyst A to give highly functionalized cyclohexanes with four stereogenic carbons including two quaternary stereocenters in excellent enantioselectivities (97 to >99% ee) and high diastereoselectivities (93:7-99:1 dr). Thus, the first organocatalytic asymmetric Henry reaction of common ketones as acceptors is shown.