Biphenyl-Based Bis(thiourea) Organocatalyst for Asymmetric and syn-Selective Henry Reaction
作者:Pavel Bobal、Jan Otevrel
DOI:10.1055/s-0036-1588594
日期:——
excellent enantioselectivities. The achieved high reactivity and enantioselectivity in the nitroaldol reaction of nitroalkanes with aromatic aldehydes suggests promising potential for this catalyst. Moreover, a significant syn-diastereoselectivity was observed. A scalable, efficient and chromatography-free synthesis of a new enantiopure C 2-symmetric bis(thiourea) catalyst was accomplished from a readily
Abstract A series of chiral tridentate Schiff-base ligands and their polymer-supported ligands were conveniently prepared and introduced as copper(II) chiralcomplexes for the asymmetric Henry reaction. The structures of these ligands have been characterized by IR, 1 H NMR, 13 C NMR and MS. The experimental results showed that the corresponding β-nitro alcohols were obtained in moderate to high yields
摘要 一系列手性三齿席夫碱配体及其聚合物负载的配体被方便地制备并作为铜(II)手性配合物引入不对称亨利反应。这些配体的结构已通过 IR、 1 H NMR、 13 C NMR 和 MS 表征。实验结果表明,在温和条件下,以中等至高产率(高达98%)获得了相应的β-硝基醇,ee高达98%。由铜 (II) 聚合物负载的配体形成的复杂催化剂可以通过简单的过滤回收并至少重复使用 6 次,具有类似的良好催化效果(约 94% 的产率和 90% 的 ee)。
Cu-catalyzed asymmetric Henry reaction promoted by chiral camphor Schiff bases
作者:Tangqian Jiao、Jingxuan Tu、Gaoqiang Li、Feng Xu
DOI:10.1016/j.molcata.2016.02.004
日期:2016.5
Abstract Five novel chiral camphor Schiffbases have been synthesized and utilized as ligands in asymmetric Henry reaction between nitromethane and aldehydes. The diastereoisomeric Schiffbases 5a and 5a' were separated successfully and gave completely different absolute configurations in the reaction. The reactions were carried out with CuCl-Schiff base 5a complex under mild condition with good yields
Enantioselective Henry reaction catalyzed by C2-symmetric chiral diamine–copper(II) complex
作者:Sermadurai Selvakumar、Dhanasekaran Sivasankaran、Vinod K. Singh
DOI:10.1039/b904254g
日期:——
A copper(II) complex of C2-symmetric diamine has been proved to be an efficient catalyst for the enantioselective Henry reaction between nitroalkanes and various aldehydes to provide β-hydroxy nitroalkanes in high yields (up to 97%), moderate diastereoselectivities (up to 71:29) and excellent enantiomeric excesses (up to 96%). The chiral nitroaldol adduct obtained has been further converted into chiral
the best of our knowledge, KRED-mediated reduction of class II α-nitro ketones (1-aryloxy-3-nitro-2-propanone (4)) is unprecedented. Select β-nitro alcohols, including the synthetic intermediates of bioactive molecules (R)-tembamide, (S)-tembamide, (S)-moprolol, (S)-toliprolol and (S)-propanolol, were stereoselectively synthesized in preparative scale with 42% to 90% isolated yields, showcasing the