GaBr₃-Catalyzed Coupling between α-Iodo Esters with Alkynylstannanes under UV Irradiation

Abstract

A coupling between various alkynylstannanes with α-iodo esters was catalyzed by GaBr₃ under UV irradiation conditions, for which a catalytic amount of GaBr₃ was essential, and a radical coupling with the generated alkynylgallium species was involved. The desired α-alkynyl esters were selectively obtained even in the presence of an aryl-I bond, which is a reactive site in a conventional palladium-catalyzed system.