Synthesis of -Nitro--diazocarbonyl Derivatives and Their Applications in the Cyclopropanation of Alkenes and in OH Insertion Reactions
作者:André B. Charette、Ryan P. Wurz、Thierry Ollevier
DOI:10.1002/hlca.200290023
日期:2002.12
a diazo-transfer reaction involving (trifluoromethyl)sulfonyl azide has been developed. These substrates undergo a rhodium-catalyzedcyclopropanation reaction with a variety of alkenes. A systematic study of the reaction indicated that the diastereoselectivity of the cyclopropanation could be effectively controlled through the modification of the steric bulk of the diazo reagent. A novel OH insertion
Organocatalytic asymmetric Michael/hemiacetalization/acyl transfer reaction of α-nitroketones with <i>o</i>-hydroxycinnamaldehydes: synthesis of 2,4-disubstituted chromans
作者:Rajendra Maity、Subhas Chandra Pan
DOI:10.1039/c8ob00078f
日期:——
An organocatalyticasymmetriccascadeMichael/hemiketalization/acyl transfer reaction between o-hydroxycinnamaldehydes and α-nitroketones is developed. Prolinol TMS ether catalyst in combination with benzoic acid was found to be the most effective for this reaction which proceeds through an equilibrium of lactols to provide a single diastereomer of enantiopure 2,4-disubstituted chromans.
α-Nitro-α,β-Unsaturated Ketones: An Electrophilic Acyl Transfer Reagent in Catalytic Asymmetric Friedel–Crafts and Michael Reactions
作者:Chandrakanta Parida、Rajendra Maity、Subas Chandra Sahoo、Subhas Chandra Pan
DOI:10.1021/acs.orglett.9b02310
日期:2019.9.6
α-nitro-α,β-unsaturated ketones as efficient electrophilic acyl transfer reagents, and they were employed in Friedel-Crafts as well as in Michael reactions. The desired acyl transfer products of these reactions were obtained in high yields with high to excellent enantioselectivities with t-leucine-derived squaramide catalyst under mild reaction conditions. Few applications including a synthesis of the isoxazoline
Organocatalytic Asymmetric Michael/Hemiketalization/Retro-aldol Reaction of α-Nitroketones with Unsaturated Pyrazolones: Synthesis of 3-Acyloxy Pyrazoles
作者:Rajendra Maity、Chandan Gharui、Arun K. Sil、Subhas Chandra Pan
DOI:10.1021/acs.orglett.6b03823
日期:2017.2.3
An organocatalyticasymmetriccascadeMichael/hemiketalization/retro-aldol reaction between unsaturated pyrazolones and α-nitroketones is described. A bifunctional thiourea catalyst was found to be efficient for this reaction. With 10 mol % of catalyst, high yields as well as excellent enantioselectivities are attained for a variety of 3-acyloxy pyrazoles under mild reaction conditions.
Enantio- & chemo-selective preparation of enantiomerically enriched aliphatic nitro alcohols using Candida parapsilosis ATCC 7330
作者:Sowmyalakshmi Venkataraman、Anju Chadha
DOI:10.1039/c5ra13593a
日期:——
asymmetric reduction of aliphaticnitroketones was carried out in water with ethanol as cosolvent and glucose as cosubstrate using the whole cells of Candida parapsilosis ATCC 7330 in much lesser time (4 h). For the first time, the biocatalytic asymmetric reduction of the following ketones is reported here: 1-nitro-butan-2-one, 1-nitro-pentan-2-one, 3-methyl-1-nitro-butan-2-one and 1-cyclohexyl-2-nitroethanone