Highly Enantioselective 1,4-Michael Additions of Nucleophiles to Unsaturated Aryl Ketones with Organocatalysis by Bifunctional Cinchona Alkaloids
作者:Cristina G. Oliva、Artur M. S. Silva、Diana I. S. P. Resende、Filipe A. A. Paz、José A. S. Cavaleiro
DOI:10.1002/ejoc.201000273
日期:——
The development of general and efficient asymmetric organocatalytic additions of malononitrile and nitromethane to 1,5-diarylpenta-2,4-dien-1-ones (cinnamylideneacetophenones) catalyzed by cinchona organocatalysts is reported. The reactions afforded excellent enantioselectivities (up to 99 %), high yields (up to 97 %), and exclusive 1,4-addition regioselectivities. The potential of these new enantioselective
and environmental friendly domino multicomponent reaction to construct new cyclohexanederivatives with five new stereocenters, one of them quaternary, under phase-transfer catalysis is reported. This novel one-pot reaction allows the transformation of very simple starting materials into pentasubstituted cyclohexanederivatives bearing hydroxy, nitro, and ketone moieties and involving the formation of
Ruthenium(<scp>ii</scp>)-catalyzed regioselective 1,6-conjugate addition of umpolung aldehydes as carbanion equivalents
作者:Hyotaik Kang、Chao-Jun Li
DOI:10.1039/d1sc03732c
日期:——
addition of carbon nucleophiles to electron-deficient ketones. Yet, 1,6-conjugate additions of extended conjugated systems largely remain underexplored due to difficulties in controlling the regioselectivity. Herein, we report umpolung aldehydes as carbanion equivalents for highly regioselective 1,6-conjugate addition reactions to unsaturated ketones, with preliminary studies of the enantioselective variant
构建 C-C 键的最有效和最可靠的方法之一涉及将碳亲核试剂共轭加成到缺电子酮上。然而,由于难以控制区域选择性,扩展共轭体系的 1,6-共轭添加在很大程度上仍未得到充分探索。在这里,我们报告了 umpolung 醛作为碳负离子等价物,用于对不饱和酮进行高度区域选择性的 1,6-共轭加成反应,并对对映选择性变体进行了初步研究。钌( II )催化剂和富电子二齿膦配体的协同作用对于温和反应条件下的反应性和选择性至关重要。
Asymmetric Direct Michael Addition of Acetophenone to α,β-Unsaturated Aldehydes
The asymmetric direct Michaeladdition of α,β-unsaturated aldehydes with acetophenone catalyzed by a Jørgensen-Hayashi catalyst in methanol was developed and the corresponding Michael products of δ-keto aldehydes could be afforded in up to 82% yield and 98% ee. asymmetric catalysis - Michaeladditions - ketones - aldehydes - enals
Synthesis, biological evaluation and QSAR studies of diarylpentanoid analogues as potential nitric oxideinhibitors
作者:S. M. Mohd Faudzi、S. W. Leong、F. Abas、M. F. F. Mohd Aluwi、K. Rullah、K. W. Lam、S. Ahmad、C. L. Tham、K. Shaari、N. H. Lajis
DOI:10.1039/c4md00541d
日期:——
A series of forty-five diarylpentadienone analogues were synthesized and were screened for their anti-inflammatory properties. Compound 7d had potent nitric oxide (NO) activity with an IC50 value of 10.24 μM.