The reaction of γ-alkenyl-γ-butyrolactones with allylic trimethylsilanes in the presence of trimethyloxonium tetrafluoroborate proceeded regio- and stereoselectively with an allylic rearrangement of the substrate to afford methyl (E)-4,8-alkadienoates in high yields. On the other hand, the ring opening of 4-hexen-6-olide afforded exclusively methyl (Z)-4,8-alkadienoates in high yields. The synthetic utility of the reaction was demonstrated by the short step synthesis of β-sinensal and β-farnesene.
γ-烯基-
γ-丁内酯与烯丙基三甲基
硅烷在
三甲基氧鎓四
氟硼酸盐存在下的反应,经过区域和立体选择性,底物发生烯丙重排,生成了高产率的甲基 (E)-4,8-烯二酸酯。另一方面,4-己烯-6-内酯的开环反应则专门生成高产率的甲基 (Z)-4,8-烯二酸酯。这一反应的合成实用性通过β-
辛烯醛和β-法尼烯的短步合成得到了验证。