Highly effective and enantioselective Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketones promoted by simple chiral primary amine thiourea bifunctional catalysts
作者:Ren-Qiang Mei、Xiao-Ying Xu、Yan-Chun Li、Ji-Ya Fu、Qing-Chun Huang、Li-Xin Wang
DOI:10.1016/j.tetlet.2011.01.054
日期:2011.4
Highly asymmetric Michael addition of 4-hydroxycoumarin to α,β-unsaturatedketones promoted by chiral primary amine thiourea bifunctional catalysts was developed and a series of Michael adducts were obtained in excellent yields (up to 97%) and enantioselectivities (up to 95% ee). Optically pure S-warfarin was easily obtained in 99% ee after single recrystallization.
secondary amine amide catalysts were developed for the asymmetric Michaeladdition of 4-hydroxycoumarin to α,β-unsaturated ketones. A series of important biologically and pharmaceutically active compounds were obtained in excellent yields (up to 99 %) with high enantioselectivities (up to 89 % ee) under mild conditions. In addition, enantiopure product could be obtained by a single recrystallization
Chiral primary amino amide organocatalysts were designed and synthesized as new organocatalysts for the enantioselective Michael addition of 4-hydroxycoumarin with alpha,beta-unsaturated ketones to produce chiral warfarin (up to 56% ee with up to 92% yield).