Please use this identifier to cite or link to this item: http://lib.jncasr.ac.in:8080/jspui/handle/10572/2469
Title: Conformational change in a urea catalyst induced by sodium cation and its effect on enantioselectivity of a Friedel-Crafts reaction
Authors: Chittoory, Arjun K.
Kumari, Gayatri
Mohapatra, Sudip
Kundu, Partha P.
Maji, Tapas K.
Narayana, Chandrabhas
Rajaram, Sridhar
Keywords: Organic Chemistry
Sulfonyl Urea
Hydrogen-Bonding Catalysts
Conformational Control
Ir And Raman Spectroscopy
Lewis-Acid Coordination
Hydrogen-Bond Donors
Asymmetric Catalysis
Phosphine Complexes
Thioacetic Acid
Metal-Free
Nitroalkenes
Alkylation
Indoles
Organocatalysis
Issue Date: 2014
Publisher: Pergamon-Elsevier Science Ltd
Citation: Chittoory, AK; Kumari, G; Mohapatra, S; Kundu, PP; Maji, TK; Narayana, C; Rajaram, S, Conformational change in a urea catalyst induced by sodium cation and its effect on enantioselectivity of a Friedel-Crafts reaction. Tetrahedron 2014, 70 (21) 3459-3465, http://dx.doi.org/10.1016/j.tet.2014.03.068
Tetrahedron
70
21
Abstract: While developing bis-camphorsulfonyl urea as a hydrogen-bonding catalysts, we discovered that the native conformation of the catalyst is unsuitable for inducing enantioselectivity. By complexing the catalyst with weakly Lewis acidic sodium cations, we were able to change the conformation of the catalyst and attain a significant improvement in the selectivity. We provide structural information from X-ray crystallography to show that the uncomplexed catalyst is indeed in an unfavorable conformation. Infrared and Raman spectroscopic studies show that sodium binds the catalyst through the carbonyl and sulfonyl groups. Simulated IR and Raman spectra match well with the experimentally recorded spectra, thereby corroborating the proposed conformational change. This result shows that weak Lewis acids can be used to tune the conformation of hydrogen-bonding catalysts and enhance the selectivity of reaction catalyzed by these systems. (C) 2014 Elsevier Ltd. All rights reserved.
Description: Restricted Access
URI: http://hdl.handle.net/10572/2469
ISSN: 0040-4020
Appears in Collections:Research Articles (Chandrabhas N.)
Research Articles (Sridhar Rajaram)

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