Enantioselective Conversion of Achiral Cyclohexadienones to Chiral Cyclohexenones by Desymmetrization
作者:Yixin Han、Simon Breitler、Shao-Liang Zheng、E. J. Corey
DOI:10.1021/acs.orglett.6b03186
日期:2016.12.2
The enantioselective reduction of prochiral 4,4-disubstituted 2,5-cyclohexadienones to chiral 2-cyclohexenones has been accomplished by the use of a carefully selected chiral bisphosphine–CuI complex and diisobutylaluminum hydride–hexamethylphosphoric triamide complex. This reagent has provided access to a key bicyclic intermediate for the total synthesis of the natural enantiomer of the pentacyclic
通过使用精心选择的手性双膦-CuI复合物和氢化二异丁基铝-六甲基磷酸三酰胺复合物,可以实现将手性4,4-二取代的2,5-环己二酮对映体选择性还原为手性2-环己烯酮。该试剂提供了关键的双环中间体的途径,用于全合成五环酯基戊二烯-维生素A酸的天然对映异构体,其中涉及CH 3和CH 2 CH 2 R取代基之间的空间区分,该操作以前是难以捉摸的。另外,描述了第二种去对称化方法,该方法使用环戊二烯催化手性对映体选择性[4 + 2]-环加成至前手性4,4-二取代的2,5-环己二酮。