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Kwame Nkrumah University of Science and Technology
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Papers by Anita Adams
Theoretical Chemistry Accounts, 2020
1,3-Dipolar cycloaddition of nitrones to oxanorbornadienes is an important method for the enantio... more 1,3-Dipolar cycloaddition of nitrones to oxanorbornadienes is an important method for the enantioselective synthesis of highly substituted 5-membered heterocycles such as furans and isoxazolidines, which have high utility in the chemical and pharmaceutical industries. The mechanism of the reaction and the effects of substituents on the (3 + 2) cycloaddition reactions (32CA) of C,N-dialkyl nitrones with a series of substituted oxanorbornadienes have been studied with focus on the site-selectivity (attack on the more substituted double bond of the oxanorbornadiene derivatives versus attack on the less substituted double bond), enantioselectivity and stereo-selectivity using density functional theory calculations at the M06/6-311++G(d,p) of theory. The results showed that the addition step to form the bicyclic isoxazolidines cycloadducts has generally low barriers compared to the cycloreversion step which converts the cycloadducts into furans and monocyclic isoxazolidines. Generally, electron-withdrawing substituents favour the nitrone attack on the highly substituted double bond, while electron-donating substituents favour the attack on less substituted double bond. The R enantiomers are generally favoured over the S enantiomers, and exo stereo-isomers are generally favoured over the endo stereo-isomers, irrespective of substituents.
Journal of Molecular Graphics and Modelling, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Theoretical Chemistry Accounts, 2020
1,3-Dipolar cycloaddition of nitrones to oxanorbornadienes is an important method for the enantio... more 1,3-Dipolar cycloaddition of nitrones to oxanorbornadienes is an important method for the enantioselective synthesis of highly substituted 5-membered heterocycles such as furans and isoxazolidines, which have high utility in the chemical and pharmaceutical industries. The mechanism of the reaction and the effects of substituents on the (3 + 2) cycloaddition reactions (32CA) of C,N-dialkyl nitrones with a series of substituted oxanorbornadienes have been studied with focus on the site-selectivity (attack on the more substituted double bond of the oxanorbornadiene derivatives versus attack on the less substituted double bond), enantioselectivity and stereo-selectivity using density functional theory calculations at the M06/6-311++G(d,p) of theory. The results showed that the addition step to form the bicyclic isoxazolidines cycloadducts has generally low barriers compared to the cycloreversion step which converts the cycloadducts into furans and monocyclic isoxazolidines. Generally, electron-withdrawing substituents favour the nitrone attack on the highly substituted double bond, while electron-donating substituents favour the attack on less substituted double bond. The R enantiomers are generally favoured over the S enantiomers, and exo stereo-isomers are generally favoured over the endo stereo-isomers, irrespective of substituents.
Journal of Molecular Graphics and Modelling, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.