作者:Patrick Metzner、Thi Nhan Pham、Jean Vialle
DOI:10.1016/s0040-4020(01)87619-5
日期:1986.1
dithioacetals leads to diethylenic dithioesters under mild conditions (from 20°C to 100°C). The thio-Claisen transposition is thus confirmed as a facile sigmatropic shift. It is also demonstrated that the reverse reaction (retro thio-Claisen) proceeds simultaneously. The equilibrium mixture of ketene dithioacetal and dithioester ie usually in the range of 70 : 30 to 95 : 5. Thiophilic addition to these diunsaturated
已经研究了用LDA使β-不饱和二硫代酸酯去质子化的立体化学:立体化学纯的二烯硫醇酯是由丁烯-3-二硫代乙酸甲酯形成的。二烯硫醇锂的质子化主要提供共轭的不饱和二硫酯。二烯硫醇盐与烯丙基溴的S-烷基化定量地提供了S-烯丙基烯酮二硫缩醛。这些二硫缩醛的热重排导致在温和的条件下(从20°C到100°C)形成二烯基二硫代酸酯。因此,硫代-克莱森换位被确认为容易的σ移。还证明了逆反应(逆硫代-克莱森)同时进行。乙烯酮二硫缩醛和二硫酯的平衡混合物,即通常在70:30至95:5的范围内。向这些二不饱和二硫代酯中进行亲脂加成,然后用烷基卤化物处理,得到二不饱和二硫代缩醛。这些被掩盖的酮可以被认为是由β-不饱和酮的α区域选择性烯丙基化引起的。