Asymmetric Hydrosilylation of Ketones Using<b><i>Trans</i></b>-Chelating Chiral Peralkylbisphosphine Ligands Bearing Primary Alkyl Substituents on Phosphorus Atoms
作者:Ryoichi Kuwano、Masaya Sawamura、Junya Shirai、Masatoshi Takahashi、Yoshihiko Ito
DOI:10.1246/bcsj.73.485
日期:2000.2
Asymmetric hydrosilylation of simple ketones with diphenylsilane proceeded at -40 °C in the presence of a rhodium complex (0.001—0.01 molar amount) coordinated with a trans-chelating chiral bisphosphine ligand bearing linear alkyl substituents on the phosphorus atoms, (R,R)-(S,S)-Et-, Pr-, or BuTRAP, giving the corresponding optically active (S)-secondary alcohols with up to 97% ee. The asymmetric
简单酮与二苯基硅烷的不对称氢化硅烷化在 -40 °C 下在铑配合物(0.001-0.01 摩尔量)存在下进行,该配合物与在磷原子上带有线性烷基取代基的反式螯合手性双膦配体(R,R) -(S,S)-Et-、Pr- 或 BuTRAP,得到相应的光学活性 (S)-仲醇,其 ee 高达 97%。使用具有更大 P 取代基的 TRAP 配体的不对称氢化硅烷化导致低得多的对映选择性。EtTRAP-铑催化剂对于具有铑原子配位位点的酮酯的不对称氢化硅烷化也有效(高达 98% ee)。通过使用 2.5 摩尔二苯基硅烷的不对称还原,从相应的二酮中获得了高达 99% ee 的旋光对称二醇。