Reactivity and Enantioselectivity in the Reactions of Scalemic Stereogenic α-(<i>N</i>-Carbamoyl)alkylcuprates
作者:R. Karl Dieter、Gabriel Oba、Kishan R. Chandupatla、Chris M. Topping、Kai Lu、Rhett T. Watson
DOI:10.1021/jo035845i
日期:2004.4.1
ine and THF soluble CuCN·2LiCl react with vinyl iodides, vinyl triflates, β-iodo-α,β-enoates, propargyl mesylates, and allyl bromide to afford the substitution products with excellent enantioselectivity. Excellent enantiomeric ratios are obtained in the conjugate addition reactions with methyl vinyl ketone while low enantiomeric ratios can be achieved with acrylate esters using HMPA/TMSCl activation
由鳞状(即对映体富集的)N制备的立体异构2-(N-氨基甲酰基)吡咯烷基铜酸盐-Boc-2-lithiopyrrolidine和THF可溶性CuCN·2LiCl与乙烯基碘,乙烯基三氟甲磺酸酯,β-碘-α,β-烯酸酯,炔丙基甲磺酸酯和烯丙基溴反应,可提供具有出色对映选择性的取代产物。在与甲基乙烯基酮的共轭加成反应中获得了出色的对映体比率,而使用HMPA / TMSCl活化的丙烯酸酯可以实现低对映体比率。对映体比率随底物取代模式而变化,并且所观察到的对映选择性似乎比反应类型(例如,取代,共轭物添加)更多地是铜酸盐-亲电子反应性的函数。α-(N-氨基甲酰基)苄基铜酸酯。锂-铜的金属转移和铜酸盐的乙烯基化反应会继续保持构型。