Stereospecific phenylthio migrations in the synthesis of spirocyclic lactones and ethers from N-methyl-4-piperidone and quinuclidin-3-one

Abstract

Single diastereoisomers of spirocyclic lactones and ethers have been prepared using intramolecular attack by the oxygen atom of a hydroxy or ester group onto an episulfonium ion. The sulfur group migrates with complete stereospecificity to give the saturated oxygen heterocycle based on the piperidine or quinuclidine ring.