Highly Productive CNN Pincer Ruthenium Catalysts for the Asymmetric Reduction of Alkyl Aryl Ketones
作者:Walter Baratta、Giorgio Chelucci、Santo Magnolia、Katia Siega、Pierluigi Rigo
DOI:10.1002/chem.200802112
日期:2009.1.5
Josiphos=1‐[1‐(dicyclohexylphosphano)ethyl]‐2‐(diarylphosphano)ferrocene) have been prepared by treating [RuCl2(PPh3)3] with (S,R)‐Josiphos diphosphanes and 1‐substituted‐1‐(6‐arylpyridin‐2‐yl)methanamines (HCNN; substituent=H (1 a), Me (1 b), and tBu (1 c)) with NEt3. By using 1 b and 1 c as a racemic mixture, complexes 4–7 were obtained through a diastereoselective synthesis promoted by acetic acid. These pincer
手性钌钳形式将[RuCl(CNN)(Josiphos)](络合物2 - 7 ; Josiphos = 1- [1-(dicyclohexylphosphano)乙基] -2-(diarylphosphano)二茂铁)已经制备通过处理将[RuCl 2(PPH 3)3 ]与(S,R)-Josiphos二膦和1-取代的-1-(6-芳基吡啶-2-基)甲胺(HCNN;取代基= H(1 a),Me(1 b)和t Bu (1 c))与NEt 3。通过使用1 b和1 c作为外消旋混合物,可以形成配合物4 – 7通过乙酸促进的非对映选择性合成而获得。这些钳形配合物显示出正确匹配的手性PP和CNN配体,是显着的活性催化剂,可通过转移氢化(TH)和氢化(HY)来不对称还原碱性醇介质中的烷基芳基酮,对映选择性高达99% 。在2-丙醇中,酮的对映选择性TH是通过使用低至0.002 mol%的催化剂实现的,其周转频率(TOF)为10