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Title: Carbene-catalyzed alkylation of carboxylic esters via direct photoexcitation of acyl azolium intermediates
Authors: Ren, Shi-Cao
Lv, Wen-Xin
Yang, Xing
Yan, Jia-Lei
Xu, Jun
Wang, Fang-Xin
Hao, Lin
Chai, Huifang
Jin, Zhichao
Chi, Robin Yonggui
Keywords: Science
Issue Date: 2021
Source: Ren, S., Lv, W., Yang, X., Yan, J., Xu, J., Wang, F., Hao, L., Chai, H., Jin, Z. & Chi, R. Y. (2021). Carbene-catalyzed alkylation of carboxylic esters via direct photoexcitation of acyl azolium intermediates. ACS Catalysis, 11(5), 2925-2934.
Journal: ACS Catalysis
Abstract: A carbene-catalyzed reductive coupling reaction of carboxylic esters and substituted Hantzsch esters is disclosed. Key steps of this reaction include one-electron reduction of a carbene catalyst-bound acyl azolium intermediate to generate the corresponding radical intermediate for subsequent alkylation reactions. The reaction is promoted by irradiation with visible light without the involvement of transition-metal photocatalysts. Mechanistic studies suggest that direct photoexcitation of the in situ formed acyl azolium intermediate is likely responsible for this light-induced one-electron-reduction process. Photoexcitation converts the acyl azolium intermediate to a single-electron oxidant, enabling single-electron oxidation of Hantzsch esters to generate radical intermediates. Our reactions work well for a broad range of aryl carboxylic ester and Hantzsch ester substrates. Sophisticated structures, including those present in medicines, can be incorporated into ketone molecules using our approach via very mild conditions that tolerate various functional groups.
ISSN: 2155-5435
DOI: 10.1021/acscatal.1c00165
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SPMS Journal Articles

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