Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups

The effect of ortho′-substituted side chains bearing nucleophilic groups such as CH 2 OH, CH 2 NHR, and CO 2 H on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals was investigated, and results were compared with those of substrates where the nucleophilic gr...

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Main Authors: Chong, Kam Weng, Thomas, Noel Francis, Low, Yun Yee, Kam, Toh Seok
Format: Article
Published: American Chemical Society 2018
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Online Access:http://eprints.um.edu.my/22206/
https://doi.org/10.1021/acs.joc.8b02360
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spelling my.um.eprints.222062019-09-04T04:18:07Z http://eprints.um.edu.my/22206/ Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups Chong, Kam Weng Thomas, Noel Francis Low, Yun Yee Kam, Toh Seok Q Science (General) QD Chemistry The effect of ortho′-substituted side chains bearing nucleophilic groups such as CH 2 OH, CH 2 NHR, and CO 2 H on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals was investigated, and results were compared with those of substrates where the nucleophilic groups such as OH and NHR are directly attached to the aromatic ring. It was found that when ortho′-substituted groups such as CH 2 OH or CH 2 NHR are present in the other ring, only direct intramolecular cation-nucleophile reactions occur to give bisbenzopyrans or bisisoquinolines. Crossover products (previously obtained when the ortho′ substituents were OH and NH 2 ) such as the fused benzoxepanes/fused benzoazepanes were not formed. When the ortho′ substituent is COOH, direct intramolecular cation-nucleophile reaction occurs to give the corresponding bis-δ-lactones in high yield. The presence of an additional 3-methoxy substituent resulted in the formation of other fused polycyclic products due to competing aromatic substitution reactions. Reaction pathways leading to the different products and reasons for the difference in behavior shown by the present stilbenes are presented. The results have provided additional insight into the reactivity and behavior of anodically generated stilbene cation radicals. American Chemical Society 2018 Article PeerReviewed Chong, Kam Weng and Thomas, Noel Francis and Low, Yun Yee and Kam, Toh Seok (2018) Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups. The Journal of Organic Chemistry, 83 (24). pp. 15087-15100. ISSN 0022-3263 https://doi.org/10.1021/acs.joc.8b02360 doi:10.1021/acs.joc.8b02360
institution Universiti Malaya
building UM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaya
content_source UM Research Repository
url_provider http://eprints.um.edu.my/
topic Q Science (General)
QD Chemistry
spellingShingle Q Science (General)
QD Chemistry
Chong, Kam Weng
Thomas, Noel Francis
Low, Yun Yee
Kam, Toh Seok
Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups
description The effect of ortho′-substituted side chains bearing nucleophilic groups such as CH 2 OH, CH 2 NHR, and CO 2 H on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals was investigated, and results were compared with those of substrates where the nucleophilic groups such as OH and NHR are directly attached to the aromatic ring. It was found that when ortho′-substituted groups such as CH 2 OH or CH 2 NHR are present in the other ring, only direct intramolecular cation-nucleophile reactions occur to give bisbenzopyrans or bisisoquinolines. Crossover products (previously obtained when the ortho′ substituents were OH and NH 2 ) such as the fused benzoxepanes/fused benzoazepanes were not formed. When the ortho′ substituent is COOH, direct intramolecular cation-nucleophile reaction occurs to give the corresponding bis-δ-lactones in high yield. The presence of an additional 3-methoxy substituent resulted in the formation of other fused polycyclic products due to competing aromatic substitution reactions. Reaction pathways leading to the different products and reasons for the difference in behavior shown by the present stilbenes are presented. The results have provided additional insight into the reactivity and behavior of anodically generated stilbene cation radicals.
format Article
author Chong, Kam Weng
Thomas, Noel Francis
Low, Yun Yee
Kam, Toh Seok
author_facet Chong, Kam Weng
Thomas, Noel Francis
Low, Yun Yee
Kam, Toh Seok
author_sort Chong, Kam Weng
title Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups
title_short Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups
title_full Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups
title_fullStr Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups
title_full_unstemmed Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups
title_sort reactivity of anodically generated 4-methoxystilbene cation radicals: the influence of ortho-substituted hydroxymethyl, aminomethyl, and carboxylic acid groups
publisher American Chemical Society
publishDate 2018
url http://eprints.um.edu.my/22206/
https://doi.org/10.1021/acs.joc.8b02360
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