Copper(I)‐Catalyzed Proto/Carboboration of Enyne Boronates for the Synthesis of Densely Substituted Diene Diboronates

Abstract

A copper‐catalyzed carbo‐/protoboration of boryl enynes is disclosed, providing access to an array of penta‐ and hexasubstituted diboryl dienes in a chemo‐, regio‐ and stereoselective manner. All six positions of the dienes can be manipulated using this methodology. The hexasubstituted diene boronates adopt a skew conformation. An iterative Suzuki coupling of the products provided highly conjugated trienes and tetraenes.