Cesium hydroxide-catalyzed isomerization of terminal alkynes for the synthesis of O-allenes and N-allenes

A novel and efficient method for the synthesis of O-allenes and N-allenes via isomerization of terminal alkynes catalyzed by cesium hydroxide monohydrate is described. The advantages of this method include: mild reaction conditions, high yields and wide tolerance toward functional groups. The protocol provides an efficient route to O-allenes and N-allenes, which are important intermediates in organic synthetic chemistry.