Novel Asymmetric Michael Addition of α-Cyanopropionates to Acrolein by the Use of a Bis(oxazolinyl)phenylstannane-Derived Rhodium(III) Complex as a Chiral Lewis Acid Catalyst
作者:Yukihiro Motoyama、Yoshiyuki Koga、Kouji Kobayashi、Katsuyuki Aoki、Hisao Nishiyama
DOI:10.1002/1521-3765(20020703)8:13<2968::aid-chem2968>3.0.co;2-6
日期:2002.7.3
rhodium complex prepared in situ by simply mixing [[RhCl(c-octene)2]2] and [(Phebox)SnMe3] (1) (Phebox = 2,6-bis(oxazolinyl)phenyl) was found to serve as an efficient catalyst for the asymmetric Michael addition of alpha-cyanopropionates (4) to acrolein under mild and neutral conditions. In the present catalytic system, both the temperature of catalyst preparation and the order of the addition of the
发现通过简单地混合[[RhCl(c-辛烯)2] 2]和[(Phebox)SnMe3](1)(Phebox = 2,6-双(恶唑啉基)苯基)原位制备的铑配合物在温和和中性条件下将丙烯腈丙酸酯(4)不对称迈克尔加成到丙烯醛的有效催化剂。在本催化体系中,催化剂的制备温度和底物的添加顺序对于催化效率和对映选择性都非常重要。此催化系统的详细机理研究表明,通过[[RhCl(c-辛烯)2] 2]氧化加成1生成的[(Phebox)RhIII(SnMe3)Cl]络合物(9)是活性催化剂,存在于反应混合物中的当前实际催化剂的周转数(TON)大于10,000。