factor-active drugs. The use of the piperidine catalyst and no catalyst showed very high cis-stereoselectivity (cis/trans = 10/1—50/1) during the reaction. On the other hand, the trans-selective reaction was promoted by Ti(O-i-Bu)4 and Al(O-s-Bu)3 catalysts (cis/trans = 1/8—1/25). Both reactions were conducted with higher cis- and trans-selectivities as compared with those of the alkyl 2-mercaptoalkanoates under
2-巯基链烷酸甲
硅烷酯和芳基亚甲基胺的环缩合反应具有高立体选择性,可交替生成顺式和反式 2,5-二取代 4-
噻唑烷酮,其中一些被称为抗血小板激活因子活性药物。使用
哌啶催化剂和不使用催化剂在反应过程中表现出非常高的顺式立体选择性(顺式/反式=10/1—50/1)。另一方面,Ti(Oi-Bu)4和Al(Os-Bu)3催化剂促进了反式选择性反应(顺/反=1/8—1/25)。在温和条件下,与 2-巯基链烷酸烷基酯相比,这两种反应均以更高的顺式和反式选择性进行。使用三甲基甲
硅烷基 2-(三甲基甲
硅烷基
硫基)
丙酸酯和甲基 2-(三烷基甲
硅烷基
硫基)
丙酸酯的环缩合反应在催化量 (0.