Enantioselective copper catalysed 1,4-conjugate addition reactions using chiral N-heterocyclic carbenes
作者:Caroline L. Winn、Frédéric Guillen、Julien Pytkowicz、Sylvain Roland、Pierre Mangeney、Alexandre Alexakis
DOI:10.1016/j.jorganchem.2005.07.024
日期:2005.12
The preparation of a variety of chiral N-heterocyclic carbene (NHC) precursors is described. The relative merits of imidazolinium salts and silver carbenes as NHC precursors are discussed with respect to their synthesis, stability and performance in the copper catalysed conjugate addition of dialkyl zinc reagents to a variety of Michael acceptors. Enantioselectivities of up to 93% were achieved using
描述了多种手性N-杂环卡宾(NHC)前体的制备。讨论了咪唑啉鎓盐和羧甲基银作为NHC前体的相对优点,涉及它们在铜催化的将二烷基锌试剂共轭添加到多种Michael受体中时的合成,稳定性和性能。使用低至4%的手性配体即可实现高达93%的对映选择性。