Stille Reactions of 2,3-Bis(stannyl)butenoates: An Unexpected Regioselectivity

The palladium-catalyzed cross-coupling reaction of ­methyl (Z)-2,3-bis(tributylstannyl)butenoate with aryl iodides is ­ regioselective, leading to 2-aryl-3-stannylated products; this selectivity is the opposite to that observed in the reaction between halides and 3,4-bis(stannyl)furan-2(5H)-one. Since the resulting butenoates can be converted into the corresponding furanones, the method ­provides useful flexibility in the preparation of functionalized butenoates and furanones.