Solvent-Controlled, Atom-Economic, and Highly Regio- and Stereoselective Halo-Chalcogenations of Ynamides: Green Synthesis of Stereodefined Tetrasubstituted Alkenes Bearing Four Different Functional Groups

The synthesis of stereodefined tetrasubstituted alkenes bearing four different functional groups is challenging. Herein, we disclose a 100% atom-economic and highly regio- and stereoselective halo-chalcogenations, in particular, chlorosulfenylation, bromosulfenylation, chloroselenation, and bromoselenation, of ynamides in toluene at room temperature under an aerobic atmosphere for the synthesis of a wide variety of stereodefined tetrasubstituted alkenes bearing four different functional groups in excellent yields. Notably, all the reactions are highly efficient and furnished the desired products in excellent yield (average yield >96%) and stereoselectivity (