Palladium‐Catalyzed Oxidative Sulfamidation: A Stereoselective Synthesis for Enesulfonamides

Abstract

AbstractA palladium‐catalyzed protocol involving oxidative C–H sulfamidation of electron‐deficient terminal alkenes is described for the stereoselective synthesis of Z‐enesulfonamides. The possible intramolecular hydrogen bonding between the sulfamido proton (SO2N–H) and the carbonyl oxygen (C=O) of the ester group provides extra stability to the resulting alkyl‐palladium complex as well as to the transition state. Notably, this reaction operates at room temperature under ligand‐free conditions and does not require any inert atmosphere or dry solvent or expensive terminal oxidant. The present protocol enables the stereoselective synthesis of Z‐enesulfonamides from the primary sulfonamides and of E‐enesulfonamides from N‐substituted sulfonamides. Furthermore, the selective deallylation of sulfonamides in the presence of an N‐benzyl group was performed under the above reaction conditions.magnified image