One‐Pot Synthesis of Cyclopropanes from Methylene Azabicyclo[3.1.0]hexanes Obtained by Formal Sequential [1+2]‐ and [2+3]‐Cycloaddition Reaction of Prop‐2‐ynylsulfonium Salts and Tosylaminomethyl Enones

A formal sequential [1+2]‐ and [2+3]‐annulation of prop‐2‐ynylsulfonium salts and tosylaminomethyl enones was developed, constructing a series of methylene azabicyclo[3.1.0]hexane derivatives. A one‐pot procedure was established via hydration of an enamine intermediate to afford substituted cyclopropanes. Prop‐2‐ynylsulfonium salts acted as both C 2 and C 1 synthons in these two processes. magnified image