Copper-Catalyzed Highly Efficient Multicomponent Reactions: Synthesis of 2-(Sulfonylimino)-4-(alkylimino)azetidine Derivatives

Under very mild conditions, functionalized 2-(sulfonylimino)-4-(alkylimino)azetidine derivatives were prepared in good to excellent yields via a copper-catalyzed multicomponent reaction of readily available terminal alkynes, sulfonyl azides, and carbodiimides without the assistance of a base. The mechanism may be through a [2 + 2] cycloaddition.