A zinc or indium-mediated Barbier-type addition reaction of 2,3-allenals with allyl bromide in a mixed medium of aqueous NH4Cl and THF (5 : 2) was developed to provide an efficient route to 1,5,6-alkatrien-4-ols, which is synthetically very useful. No 1,4-addition reaction was observed. Depending on the substrates, both indium and activated zinc afforded the 1,2-addition products in moderate to excellent yields: for terminal allenals, activated zinc was better while in other cases the yields with indium were relatively higher.
开发了一种
锌或
铟催化的Barbier型加成反应,将2,3-烯
丙醛与
溴代烯丙基在
氟化铵和THF的混合介质(5:2)中反应,提供了一条有效的合成1,5,6-烯
三烯-4-醇的路径,这在合成上非常有用。未观察到1,4-加成反应。根据底物的不同,
铟和活化
锌均可在中等到优良的产率下提供1,2-加成产物:对于末端烯
丙醛,活化
锌表现更好,而在其他情况下,
铟的产率相对较高。