Palladium‐Catalyzed Coupling of Propargylic Carbonates with <i>N</i>‐Tosylhydrazones: Highly Selective Synthesis of Substituted Propargylic <i>N</i>‐Sulfonylhydrazones and Vinylallenes

Abstract

An efficient palladium-catalyzed coupling of propargylic carbonates (1) with N-tosylhydrazones (2, 2′) has been carried out. A wide range of propargylic N-sulfonylhydrazones (3) and multisubstituted vinylallenes (4) can be obtained selectively by using either [PdCl2(CH3CN)2] or [Pd2(dba)3] as catalysts. (dba=trans,trans-dibenzylideneacetone, dppp=propane-l,3-diylbis(diphenylphosphane), Ts=4-toluenesulfonyl.)