Matteson homologation of organoboronates is an attractive approach for constructing aliphatic carbon chains via iterative insertion of carbenoids. However, the corresponding homologation that can introduce alkene moieties to molecular backbones remains elusive. Here we report the development of a stereoselective vinylene homologation reaction of various alkyl and aryl boronates. The reaction proceeds through diastereoselective consecutive insertion of a silyl- and an alkoxy-substituted carbenoid, followed by a Peterson-type elimination. A diverse range of alkenyl boronates can be formed in good yield and with good to excellent trans selectivity. Density functional theory calculations reveal the origin of diastereoselectivity in carbenoid insertion and how Lewis acids with different sulfide binding affinities affect the competing S_N2- and S_N1-type 1,2-boronate migration pathways with distinct levels of stereospecificity. This protocol has been applied to the programmable synthesis of piperamide-family natural products through iterative vinylene and methylene homologations. Guided by mechanistic understanding, the use of oxyphilic Lewis acids has enabled the development of a cis-selective vinylene homologation.

有机硼酸酯的 Matteson 同系化是通过迭代插入类胡萝卜素构建脂肪族碳链的一种有吸引力的方法。然而，能够将烯烃部分引入分子主链的相应同系化仍然难以捉摸。在这里，我们报告了各种烷基和芳基硼酸酯的立体选择性亚乙烯基同系化反应的进展。该反应通过甲硅烷基和烷氧基取代的类胡萝卜素的非对映选择性连续插入进行，然后进行彼得森型消除。可以以良好的收率和良好至优异的反式选择性形成多种烯基硼酸酯。密度泛函理论计算揭示了类胡萝卜素插入中非对映选择性的起源，以及具有不同硫化物结合亲和力的路易斯酸如何影响具有不同立体特异性水平的竞争性 S _N 2- 和 S _{N 1- 型 1,2-硼酸盐迁移途径。}该协议已应用于通过迭代亚乙烯基和亚甲基同系化来可编程合成哌酰胺家族天然产物。在机理理解的指导下，亲氧路易斯酸的使用使得顺式选择性亚乙烯基同系化的发展成为可能。