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.
在紫外照射条件下,GaBr3催化了各种炔基
锡与α-
碘酯之间的偶合反应,催化剂GaBr3的量至关重要,且涉及与生成的炔基铝物质的自由基偶合。即使在存在芳基–I键(在传统的
钯催化系统中为反应活性位点)的情况下,所需的α-炔基酯也能选择性获得。