Harnessing sulfilimine as an oxidizing directing group in Cp*Co(iii)-catalyzed [4+2] annulation with alkynes and 1,3-diynes

Abstract

We have developed the first Cp*Co(III)-catalyzed [4+2] annulation utilizing sulfilimine as an oxidizing directing group in a redox-neutral fashion. The N–S bond of the sulfilimine serves as an internal oxidant, thereby eliminating the need for any internal oxidant. The reaction worked with various alkynes and also exhibited an excellent regioselectivity with 1,3-diynes furnishing the 3-alkynylated isoquinolones.