Promotion of Henry reactions using Cu(OTf)2 and a sterically hindered Schiff base: access to enantioenriched β-hydroxynitroalkanes
作者:Lin Yao、Yu Wei、Pingan Wang、Wei He、Shengyong Zhang
DOI:10.1016/j.tet.2012.08.029
日期:2012.11
The steric and electronic properties of chiral Schiff base ligands derived from cinchona alkaloids were evaluated in asymmetric Henry reactions. Amongst these, the sterically hindered ligand 2 showed outstanding catalytic efficiency in the Cu(II) catalyzed asymmetric addition of nitroalkanes to a variety of aldehydes to afford the desired adducts in high yields (up to 97%) with excellent enantioselectivities
在不对称的亨利反应中评估了从金鸡纳生物碱衍生的手性席夫碱配体的空间和电子性质。其中,位阻配体2在Cu(II)催化的硝基链烷烃向多种醛的不对称加成反应中表现出出色的催化效率,从而以高收率(高达97%)提供了所需的加合物,并具有出色的对映选择性(高达99%) ee)和中等至良好的非对映选择性(最高达84:16 dr)。