Cu-catalyzed tandem cross-coupling/cyclization of aryl diazophosphonates with phenylacetylene derivatives

Abstract

We report herein the first copper-catalyzed tandem cross-coupling/cyclization of diazophosphonates with phenylacetylene derivatives, providing efficient access to three kinds of alkylphosphonate-containing heterocyclic skeletons including indole, benzofuran, and isochromene. Preliminary mechanistic studies suggest an intramolecular trapping of a propargyl phosphonate intermediate instead of an allenyl species for the cyclization step.