Synthesis of Oxa-spiro-bicyclo[2.1.1]hexane by Au/Sc Relay Catalysis

A new Au/Sc relay catalysis approach has been developed for the rapid construction of oxa-spiro-bicyclo[2.1.1]hexanes under mild conditions. This cascade reaction proceeds via a gold-catalyzed cycloisomerization followed by a Sc(OTf)₃-catalyzed [3+2] cycloaddition with bicyclo[1.1.0]butanes (BCBs) in less than 1 h.