Enantioselective Synthesis of Chiral Tetrahydroisoquinolines by Iridium-Catalyzed Asymmetric Hydrogenation of Enamines
作者:Pu-Cha Yan、Jian-Hua Xie、Guo-Hua Hou、Li-Xin Wang、Qi-Lin Zhou
DOI:10.1002/adsc.200900602
日期:2009.12
Chiral iridium complexes based on spiro phosphoramidite ligands are demonstrated to be highly efficient catalysts for the asymmetric hydrogenation of unfunctionalized enamines with an exocyclic double bond. In combination with excess iodine or potassium iodide and under hydrogen pressure, the complex Ir/(Sa,R,R)-3a provides chiral N-alkyltetrahydroisoquinolines in high yields with up to 98% ee. The
已证明基于螺亚磷酰胺配体的手性铱配合物是高效的催化剂,用于带有环外双键的未官能化烯胺的不对称氢化。与过量的碘或碘化钾结合并在氢气压力下,复合物Ir /(S a,R,R)-3a可提供高收率的手性N-烷基四氢异喹啉,ee可达98%。L / Ir比为2:1对于获得高反应速率和对映选择性至关重要。氘标记实验表明该反应中存在反同位素效应。还提出了可能的催化循环,包括带有两个单亚磷酰胺基配体的铱(III)物种。