Asymmetric catalysis. Asymmetric catalytic intramolocular hydrosilation and hydroacylation
作者:Richard W. Barnhart、Xianqi Wang、Pedro Noheda、Steven H. Bergens、John Whelan、B. Bosnich
DOI:10.1016/s0040-4020(01)89370-4
日期:1994.4
type [Rh(chiral Diphosphine)]+ efficiently catalyse the intramolecular hydrosilation of silyl ethers derived from allylic alcohol. The products can be converted to chiral 1,3-dols. High enantiomeric excesses (ee's) are observed for substrates bearing an aryl group at the olefin terminus. These same catalyst produce chiral cyclopentanones from 4-substitued 4-pentenals. Tertiary acyl and ester substituents
类型[Rh(手性二膦)] +的催化剂可有效催化衍生自烯丙醇的甲硅烷基醚的分子内硅氢化反应。产品可以转化为手性1,3-dol。对于在烯烃末端带有芳基的底物,观察到高对映体过量(ee)。这些相同的催化剂由4-取代的4-戊烯产生手性环戊酮。叔酰基和酯取代基产生几乎定量的ee。据推测,硅氢化的机理涉及甲硅烷基烯丙基的插入,而氢酰化的关键步骤可能涉及还原性消除金属环环己酮中间体。