Development of a Catalytic Asymmetric Variant of Hoppe’s <i>O</i>-Alkyl Carbamate Deprotonation Methodology
作者:Peter O’Brien、Matthew McGrath
DOI:10.1055/s-2006-942417
日期:2006.7
The optimisation of a ligand-exchange approach to catalytic asymmetric deprotonation of O-alkyl carbamates and subsequent electrophilic trapping (the ‘Hoppe reaction’) is presented. The method uses s-BuLi and sub-stoichiometric amounts of a chiral diamine [(-)-sparteine or the (+)-sparteine surrogate] in conjunction with an achiral ‘regenerating’ diamine (bisisopropyl bispidine) for the deprotonation and proceeds with good yields (up to 84%) and high enantioselectivity (up to 94:6 er). The first applications of this catalytic asymmetric deprotonation methodology in natural product synthesis are also described.
本文介绍了对催化 O-烷基氨基甲酸酯不对称去质子化及随后亲电捕集("Hoppe 反应")的配体交换方法的优化。该方法使用 s-BuLi、亚几何量的手性二胺[(-)-天冬氨酸或(+)-天冬氨酸代用品]以及非手性 "再生 "二胺(双异丙基双脒)进行去质子化反应,产率高(达 84%),对映选择性高(达 94:6er)。此外,还介绍了这种催化不对称去质子化方法在天然产物合成中的首次应用。