studies, the mechanism of these reactions was found to proceed via activation of the epoxide by the Lewis acidic borane moiety followed by nucleophilic attack of the phosphine of a second FLP molecule. The resulting chain‐like intermediates afford the final cyclic products by ring‐closure and concurrent release of the second equivalent of FLP that behaves as catalyst in this reaction.
用2-甲基
环氧乙烷,2-苯基
环氧乙烷和2-甲基
环氧乙烷处理t Bu 2 PCH 2 BPh 2(1)和o- Ph 2 P(C 6 H 4)BCat(Cat = catechol)(4) 2-(三
氟甲基)
环氧乙烷导致
环氧化物开环,分别生成六元和七元杂环2 a – c和5 a – c。这些两性离子产物进行光谱表征,和化合物2,图2b,5和通过单晶X射线结构分析对5 c进行了结构表征。基于计算和动力学研究,发现这些反应的机理是通过
路易斯酸性
硼烷部分激活
环氧化物,然后亲核攻击第二个FLP分子的膦来进行的。最终的链状中间体通过闭环并同时释放第二个等效的FLP(在该反应中起催化剂作用)而提供最终的环状产物。