Conrad Jay C, Kong Jongrock, Laforteza Brian N, MacMillan David W C
Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, USA.
J Am Chem Soc. 2009 Aug 26;131(33):11640-1. doi: 10.1021/ja9026902.
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 electron-rich aromatics and heterocycles thus efficiently providing cyclic alpha-aryl aldehyde products (10 examples: > or = 70% yield and > or = 90% ee). In accordance with our radical mechanism, when there is a choice between arylation at the ortho or para position of anisole substrates, we find that arylation proceeds selectively at the ortho position.
醛的分子内α-芳基化反应已通过单占据分子轨道（SOMO）催化实现。手性烯胺（由醛与仲胺催化剂缩合形成）的选择性氧化导致形成一个3π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侧链富电子芳烃和杂环发生对映选择性反应，从而高效地提供环状α-芳基醛产物（10个例子：产率≥70%，对映体过量值≥90%）。根据我们的自由基机理，当在苯甲醚底物的邻位或对位进行芳基化存在选择时，我们发现芳基化选择性地在邻位进行。
