Site- and Enantioselective Formation of Allene-Bearing Tertiary or Quaternary Carbon Stereogenic Centers through NHC–Cu-Catalyzed Allylic Substitution
作者:Byunghyuck Jung、Amir H. Hoveyda
DOI:10.1021/ja211269w
日期:2012.1.25
Catalytic enantioselective allylic substitutions that result in addition of an allenyl group (<2% propargyl addition) and formation of tertiary or quaternary C-C bonds are described. Commercially available allenylboronic acid pinacol ester is used. Reactions are promoted by a 5.0-10 mol % loading of sulfonate-bearing chiral bidentate N-heterocyclic carbene (NHC) complexes of copper, which exhibit the
催化对映选择性烯丙基取代,导致添加丙二烯基(<2 id=24>98% S(N)2' 选择性和 99:1 对映体比率 (er)。位点选择性 NHC-Cu 催化的对映体硼氢化反应富集丙二烯并转化为相应的β-乙烯基酮证明了该方法的实用性。