Chiral Oxazolidine‐Fused N‐Heterocyclic Carbene Complexes of Rhodium and Iridium and Their Utility in the Asymmetric Transfer Hydrogenation of Ketones
作者:Balasubramaniyam Ramasamy、Manoj Kumar Gangwar、Prasenjit Ghosh
DOI:10.1002/ejic.201700303
日期:2017.7.17
imidazolium iodide salts 1f–3f with Ag2O yielded the corresponding silver complexes 1g–3g, which were treated with [(COD)MCl]2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) to afford the rhodium(I) and iridium(I) complexes (1h–3h and 1i–3i, respectively). The rhodium(I) and iridium(I) complexes conveniently catalyze the asymmetric transfer hydrogenation of acetophenones for a wide variety of substrates ranging
在过渡金属介导的酮的不对称转移加氢反应中,已经探索了一种新的N-杂环卡宾配体的催化潜力,该配体是从手性稠合双环支架上沿带有手性助剂的C-N键旋转受限的方式开发的。特别是,手性恶唑烷稠合的N-杂环卡宾前体(3 S)-3-R-6-甲基-7-苯基-2,3-二氢咪唑并[5,1- b ]恶唑-6-碘化碘[R =仲丁基(1f),异丁基(2f),异丙基(3f)]由市售的光学纯氨基酸以多步顺序合成,避免了繁琐的手性拆分。手性碘化咪唑鎓碘化物盐1f – 3f与Ag 2 O的反应生成相应的银络合物1g – 3g,将其用[(COD)MCl] 2处理(M = Rh,Ir; COD = 1,5-环辛二烯)提供铑(I)和铱(I)络合物(1h–3h和1i – 3i, 分别)。铑(I)和铱(I)配合物可方便地催化苯乙酮的不对称转移加氢,反应范围涉及多种底物,包括富电子底物,如4-甲基苯乙酮,3,4-二甲基苯乙酮,4-叔丁