oxy-1-butene and 4-chloro-1-ethynyl-1,5-dimethyl-5-hexenyl acetate, respectively. In contrast, 3-methyl-2-butenyl derivatives 2d–f and 3-methyl-2-butenoic acid afforded a variety of products such as chlorohydrin, vinylchloride, and sulfoxide other than ene-type products, suggesting that the functional group of R in 2 affects the reaction cou...