Catalytic Hydrothiolation: Counterion-Controlled Regioselectivity

作者：Xiao‐Hui Yang, Ryan T. Davison, Shao‐Zhen Nie, Faben A. Cruz, Tristan M. McGinnis, Vy M. Dong · 发表于：Journal of the American Chemical Society · 年份：2019 · DOI：10.1021/jacs.8b11395 · 被引用次数：152 · 研究领域：Sulfur-Based Synthesis Techniques、Catalytic C–H Functionalization Methods、Chemical Synthesis and Reactions

In this Article, we expand upon the catalytic hydrothiolation of 1,3-dienes to afford either allylic or homoallylic sulfides with high regiocontrol. Mechanistic studies support a pathway in which regioselectivity is dictated by the choice of counterion associated with the Rh center. Non-coordinating counterions, such as SbF 6 –, allow for η 4 -diene coordination to Rh complexes and result in allylic sulfides. In contrast, coordinating counterions, such as Cl –, favor neutral Rh complexes in which the diene binds η 2 to afford homoallylic sulfides. We propose mechanisms that rationalize a fractional dependence on thiol for the 1,2-Markovnikov hydrothiolation while accounting for an inverse dependence on thiol in the 3,4- anti -Markovnikov pathway. Through the hydrothiolation of an essential oil (β-farnesene), we achieve the first enantioselective synthesis of (−)-agelasidine A.