4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether as a highly efficient bifunctional organocatalyst for Michael addition of ketones and aldehydes to nitroolefins
作者:Chao Wang、Chun Yu、Changlu Liu、Yungui Peng
DOI:10.1016/j.tetlet.2009.02.211
日期:2009.5
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether bifunctionalorganocatalyst 3a is a highly efficient catalyst for the asymmetric Michaeladdition reactions of ketones and aldehydes to nitrostyrenes, leading to syn-selective adducts with excellent yields (>99%), high diastereoselectivities (up to 99:1 dr) and excellent enantioselectivities (up to 99% ee). Control experiments suggested that the
A Novel Bifunctional Sulfonamide Primary Amine-Catalyzed Enantioselective Conjugate Addition of Ketones to Nitroolefins
作者:Fei Xue、Shilei Zhang、Wenhu Duan、Wei Wang
DOI:10.1002/adsc.200800445
日期:2008.10.6
The enantioselectiveconjugateaddition of a variety of ketones to nitroolefins has been developed. The process is efficiently catalyzed by a novelbifunctionalsulfonamideprimary amine in good yields and with good levels of enantioselectivity.
Michaeladditions of different aldehydes and ketones to β-nitrostyrene and 2-(β-nitrovinyl)thiophene in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) were studied. β-Nitrostyrene was a better acceptor than 2-(β-nitrovinyl)thiophene, in terms of both reactivity and selectivity. Aldehydes proved to be better donors than ketones, which were themselves better than β-diketones. L-proline proved
Readily Accessible 9-epi-amino Cinchona Alkaloid Derivatives Promote Efficient, Highly Enantioselective Additions of Aldehydes and Ketones to Nitroolefins
作者:Séamus H. McCooey、Stephen J. Connon
DOI:10.1021/ol0628006
日期:2007.2.1
from commercially available starting materials, have been shown to promote highly enantio- and diastereoselective Michael-type addition reactions between enolizable carbonyl compounds and nitroalkenes of broad scope. The influence of both the absolute and relative stereochemistry at C-9 on catalyst performance has also been assessed. [reaction: see text].
Enantioselective conjugate addition of ketones to β-nitrostyrenes catalyzed by 1,2-amino alcohol-derived prolinamides
作者:Diana Almaşi、Diego A. Alonso、Carmen Nájera
DOI:10.1016/j.tetasy.2006.07.023
日期:2006.8
Various L-prolinamides 14, prepared from L-proline and chiral beta-amino alcohols, are active bifunctional catalysts for the direct nitro-Michael addition of ketones to beta-nitrostyrenes. In particular, catalyst 14e prepared from L-proline and (1S,2R)-cis-1amino-2-indanol exhibits the highest catalytic performance working in polar aprotic solvents such as NMP. High syn-diastereoselectivities (up to 94% de) and good enantioselectivities (up to 80% ee) were obtained at rt. (c) 2006 Elsevier Ltd. All rights reserved.