99986-31-9Relevant academic research and scientific papers
α-Nitro-α,β-Unsaturated Ketones: An Electrophilic Acyl Transfer Reagent in Catalytic Asymmetric Friedel-Crafts and Michael Reactions
Parida, Chandrakanta,Maity, Rajendra,Chandra Sahoo, Subas,Chandra Pan, Subhas
, p. 6700 - 6704 (2019)
Herein, we introduce 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 motif have been demonstrated.
Catalytic Enantioselective Synthesis of 3,4,5-Trisubstituted Isoxazoline N-Oxides and Regioselective Synthesis of 3,4,5-Trisubstituted Isoxazoles
Sahoo, Subas Chandra,Pan, Subhas Chandra
supporting information, p. 1385 - 1389 (2019/01/09)
An efficient catalytic asymmetric synthesis of 3,4,5-trisubstituted isoxazoline N-oxides and regioselective synthesis of 3,4,5-trisubstituted isoxazoles has been described. α-Nitrocinnamates and α-nitrobenzophenones were utilized as Michael acceptors resp
Organocatalytic asymmetric Michael/hemiacetalization/acyl transfer reaction of α-nitroketones with o-hydroxycinnamaldehydes: Synthesis of 2,4-disubstituted chromans
Maity, Rajendra,Pan, Subhas Chandra
supporting information, p. 1598 - 1608 (2018/03/08)
An organocatalytic asymmetric cascade Michael/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.
Organocatalytic Asymmetric Domino Michael/Acyl Transfer Reaction Between α-Nitroketones and in situ-Generated ortho-Quinone Methides: Route to 2-(1-Arylethyl)phenols
Gharui, Chandan,Behera, Debasmita,Pan, Subhas Chandra
supporting information, p. 4502 - 4508 (2018/11/10)
An organocatalytic asymmetric domino Michael/acyl transfer reaction between α-nitroketones and o-quinone methides is disclosed. o-Quinone methides are generated in situ from 2-sulfonylmethylphenols in basic medium. With 10 mol% of bifunctional squaramide catalyst, high yields and excellent enantioselectivities are achieved for a variety of O-acyl 2-(1-arylethyl)phenols under mild reaction condition. (Figure presented.).
Organocatalytic Asymmetric Michael/Hemiketalization/Retro-aldol Reaction of α-Nitroketones with Unsaturated Pyrazolones: Synthesis of 3-Acyloxy Pyrazoles
Maity, Rajendra,Gharui, Chandan,Sil, Arun K.,Pan, Subhas Chandra
supporting information, p. 662 - 665 (2017/02/10)
An organocatalytic asymmetric cascade Michael/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.
Metal-free ring expansion of indoles with nitroalkenes: A simple, modular approach to 3-substituted 2-quinolones
Aksenov, Alexander V.,Smirnov, Alexander N.,Aksenov, Nicolai A.,Aksenova, Inna V.,Matheny, Jonathon P.,Rubin, Michael
, p. 8647 - 8656 (2015/03/03)
3-Substituted 2-quinolones are obtained via a novel metal-free transannulation reaction of 2-nitroolefins with 2-substituted indoles in polyphosphoric acid. This acid-mediated cascade transformation operates via the ANRORC (Addition of Nucleophile, Ring Opening, and Ring Closure) mechanism and can be used in combination with the Fisher indole synthesis to offer a practical three-component hetero-annulation approach to 2-quinolones from arylhydrazines, 2-nitroalkenes, and acetophenone. An alternative entry to this chemistry employing the alkylation of electron-rich arenes and hetarenes with 1-(2-indolyl)-2-nitroalkene has also been demonstrated.
