Asymmetric synthesis of oxa-spirocyclic indanones with structural complexity via an organocatalytic Michael-Henry-acetalization cascade

Abstract

The highly enantioselective preparation of drug-like oxa-spirocyclic indanone derivatives employing a multicomponent cascade reaction is described. This approach utilizes an organocatalytic Michael reaction followed by a Henry-acetalization sequence that yields the desired chiral spirocyclic backbone, bearing four contiguous stereogenic centers and multiple functional groups, in good yields and high stereoselectivities (up to 99% ee and 95:5 dr). © Georg Thieme Verlag Stuttgart · New York.