Palladium catalyzed coupling of organostannanes with vinyl epoxides

The coupling reaction of organotin reagents with vinyl epoxides, catalyzed by palladium, takes place at ambient temperatures, regioselectively, giving predominately the 1,4-addition product. Both aryl- and vinylstannanes undergo coupling in high yields, while acetylenic, allylic and benzylic tin reagents either give low yields or fail to couple. Although the double bond geometry in the vinylstannane partner is maintained in the coupled product, the double bond geometry from the vinyl epoxide is an E/Z mixture. In coupling reactions with cyclic 1,3-diene monoepoxides, the reaction is stereospedfic with the organic group from the tin partner coupling trans to the alcohol function.