作者:Yakup Güneş、M. Fatih Polat、Ertan Sahin、Fraser F. Fleming、Ramazan Altundas
DOI:10.1021/jo1011202
日期:2010.11.5
Quaternary oxonitriles are stereoselectively generated from the union of five-, six-, and seven-membered 2-chloroalkenecarbonitriles with chiral alcohols via a Claisen rearrangement. The strategy rests on a new conjugate addition−elimination of allylic alkoxides to 2-chlorocycloalkenecarbonitriles to afford substituted 2-alkoxyalkenenitriles. Subsequent thermolysis unmasks a cyclic oxonitrile while
五元,六元和七元的2-氯烯烃腈与手性醇通过克莱森重排的结合立体选择性地生成季腈。该策略基于新的共轭加成-将烯丙基醇盐消除到2-氯环烯腈中,得到取代的2-烷氧基烯腈。随后的热解反应会掩盖环状氧腈,同时选择性地形成对映体比率通常大于9:1的新季铵中心。整体烷基化策略解决了对映选择性地生成受阻的四级中心同时安装酮,腈和烯烃官能团的挑战。