Divergent Synthesis of Allenylsulfonamide and Enaminonesulfonamide via In(III)-Catalyzed Couplings of Propargylamine and N-Fluorobenzenesulfonimide

An In(III)-catalyzed facile and controllable method for the synthesis of allenylsulfonamide and enaminonesulfonamide has been achieved by the reaction between propargylamine and N-fluorobenzenesulfonimide (NFSI) under mild conditions. The present protocol is also applicable to the synthesis of tetrasubstituted allenylsulfonamide from triphenyl propargylalcohol. Experimental results suggest that the reaction probably proceeds through the ionic pathway.