Construction of multifunctional modules for drug discovery: synthesis of novel thia/oxa-azaspiro[3.4]octanes.

New classes of thia/oxa-azaspiro[3.4]octanes are synthesized through the implementation of robust and step-economic routes. The targeted spirocycles have been designed to act as novel, multifunctional, and structurally diverse modules for drug discovery. Furthermore, enantioselective approaches to the spirocycles are reported.