A general, highly enantioselective Michael addition of nitroalkanes to α,β-unsaturated enones catalyzed by 9-amino(9-deoxy)-epi-quinine: a remarkable additive effect
作者:Siyang Liu、Qingqing Wang、Ling Ye、Zhichuan Shi、Zhigang Zhao、Xuejun Yang、Keyi Ding、Xuefeng Li
DOI:10.1016/j.tet.2016.07.008
日期:2016.8
A particularly general protocol for the organocatalytic asymmetric Michael addition of nitroalkanes to α,β-unsaturated enones is reported. The Michaelreaction proceeded smoothly and provided the desired adducts in moderate to excellent yields (55–99%) and good to excellent enantioselectivities (65–99% ee). The addition of readily available achiral base significantly enhanced the reactivity without
Highly Enantioselective Synthesis of γ-Nitro Heteroaromatic Ketones in a Doubly Stereocontrolled Manner Catalyzed by Bifunctional Thiourea Catalysts Based on Dehydroabietic Amine: A Doubly Stereocontrolled Approach to Pyrrolidine Carboxylic Acids
作者:Xianxing Jiang、Yifu Zhang、Albert S. C. Chan、Rui Wang
DOI:10.1021/ol8025268
日期:2009.1.1
class of dehydroabietic amine-substituted primary amine-thiourea bifunctional catalysts were designed and synthesized. The doubly stereocontrolled organocatalytic conjugateaddition of a variety of heterocycles-bearing ketones to nitroalkenes was investigated for the first time, affording (S)- or (R)-γ-nitro heteroaromatic ketones with excellent enantioselectivities (up to ee >99%). Furthermore, the nearly
to 9 kbar) allows for relatively fast (1–5 h) and highlyenantioselective 1,4-addition of nitromethane and 2-nitropropane to chalcones at room temperature with substantial reduction of catalyst loading (0.2–1 mol% of cinchonaalkaloid-based thioureas and squaramides). Various γ-nitroketones were obtained at 9 kbar with high yield and enantioselectivity (up to 98%), whereas in control experiments at atmospheric
Enantioselective decarboxylative Michael addition of β-ketoacids to nitroalkenes catalyzed by binaphthyl-derived organocatalysts
作者:Hyoung Wook Moon、Dae Young Kim
DOI:10.1016/j.tetlet.2012.09.100
日期:2012.11
The catalytic enantioselective decarboxylative Michael addition reaction promoted by chiral bifunctional organocatalysts has been developed, allowing facile synthesis of the corresponding γ-nitro ketones with excellent enantioselectivity (up to 97% ee). The method reported represents a valuable approach utilizing β-ketoacids as synthetic equivalents of aryl methyl ketones.