heating in petroleum ether at 100°, 22 was transformed into a ca. 1:1 mixture of 27 and the enol ether 28. The reaction of 1 with ethyl diazoacetate (Scheme 4) in the presence of Rh2(OAc)4. 2H2O gave the unsaturated esters 29 (33%) and 30 (26%), whereas the analogous reaction with diethyl diazomalonate afforded the spirothiirane 31 (68%) and the enol ether 32 (29%). Complete transformation of 31 into 32 was
研究了将二烯,重氮甲烷和类胡萝卜素添加到甘露聚糖和核糖基配置的硫代-γ - O-内酯1和2中。因此,1(方案1)与2,3- dimethylbutadienes(反应4,73%),环戊二烯(5A / B 1:1,70%),环己-1,3-二烯(9A / B 2:3,92 %和富电子的丁二烯6(7a / b 3:1,82%)。通过快速色谱法分离5a / b的Wheers ,7a / b被去甲硅烷基化,生成噻喃酮8。一个9a / b的异亚丙基选择性水解和快速色谱分离出10a和10b。该加合物的结构通过X射线分析(阐明4)中,由NOE实验(4,5A,5B,7A / B,10A,和10B),和一个高烯丙基耦合(的基础上7A / B)。加料从选择性地发生“外切”的侧的1。仅观察到对“内基”加合物的偏爱。用阮内尼氢化9a / b-Ni(EtOH,室温)得到硫代双环[2.2.2]辛烷11。下苛刻的条件(二恶烷,110℃),9A