A Silver-Catalyzed Modular Intermolecular Access to 6,6-Spiroketals

Abstract

A modular synthesis of 6,6-spiroketals via silver catalysis is reported. By combining an intermolecular Michael addition and a 6-endo-dig cyclization, this cascade reaction allows the modular preparation of highly substituted 6,6-spiroketals by combining two substrate molecules. Established methods accessing this interesting substructure are complemented by this new transformation. The protocol tolerates diverse substitution patterns and functional groups. (Figure presented.).