作者:Stephen R. Wilson、Alexander Shedrinsky、M.Serajul Haque
DOI:10.1016/s0040-4020(01)88588-4
日期:1983.1
Metallation of 3-vinyl-5-trimethylsilyl-1-pentene (16) with π-BuLi gives a Si substituted pentadienyl anion reagent for bisannelation of ortto-alkenyl benzaldehydes. Tricyclic olefin 23b produced by this method is a homo-allylsilane which undergoes protodesilylation to 4-vinyl-12-methoxy-18,19-bisnor-podocarpa-8,11,13-triene 24b. The addition of β-(trimethylsilyl)ethyl magnesium bromide (12) to 12-methoxy-18
将3-乙烯基-5-三甲基甲硅烷基-1-戊烯(16)与π-BuLi进行金属化反应可制得Si取代的戊二烯基阴离子试剂,用于将邻甲苯基-烯基苯甲醛进行双硅烷化。通过这种方法生产的三环烯烃23b是均烯丙基硅烷,其被原去甲硅烷基化为4-乙烯基-12-甲氧基-18,19-bisnor-罗汉松-8,11,13-三烯24b。加入β-(三甲基硅基)的乙基溴化镁(12)至12甲氧基18,19 bisnor-5β-podocarpa-8,11,13-阿松香三烯三烯4 -酮27,得到相应的醇29。当29并用酸处理相关的γ-羟基硅烷,脱水成烯丙基硅烷,并进行去甲硅烷基化反应生成环外乙烯基化合物。酒精29产生的24b产率为93%。化合物24b可以通过几个步骤转化为罗汉果酸。