Enantioselective α-Arylation of Aldehydes via Organo-SOMO Catalysis. An Ortho-Selective Arylation Reaction Based on an Open-Shell Pathway
作者:Jay C. Conrad、Jongrock Kong、Brian N. Laforteza、David W. C. MacMillan
DOI:10.1021/ja9026902
日期:2009.8.26
The intramolecular alpha-arylation of aldehydes has been accomplished using singly occupied molecular orbital (SOMO) catalysis. Selective oxidation of chiral enamines (formed by the condensation of an aldehyde and a secondary amine catalyst) leads to the formation of a 3pi-electron radical species. These chiral SOMO-activated radical cations undergo enantioselective reaction with an array of pendent
醛的分子内α-芳基化已使用单占分子轨道(SOMO)催化完成。手性烯胺(由醛和仲胺催化剂缩合形成)的选择性氧化导致形成 3pi 电子自由基物种。这些手性 SOMO 活化的自由基阳离子与一系列悬垂的富电子芳烃和杂环进行对映选择性反应,从而有效地提供环状 α-芳基醛产物(10 个例子:> 或 = 70% 产率和 > 或 = 90% ee)。根据我们的自由基机制,当在苯甲醚底物的邻位或对位芳基化之间进行选择时,我们发现芳基化选择性地在邻位进行。