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Alkylboronic acids as alkylating agents: photoredox-catalyzed alkylation reactions assisted by K₃PO₄.

ABSTRACT: Despite the ubiquity of alkylboronic acids in organic synthesis, their utility as alkyl radical precursors in visible-light-induced photocatalytic reactions is limited by their high oxidation potentials. In this study, we demonstrated that an inorganophosphorus compound can modulate the oxidation potentials of alkylboronic acids so that they can act as alkyl radical precursors. We propose a mechanism based on the results of fluorescence quenching experiments, electrochemical experiments, ¹¹B and ³¹P NMR spectroscopy, and other techniques. In addition, we describe a simple and reliable alkylation method that has good functional group tolerance and can be used for direct C-B chlorination, cyanation, vinylation, alkynylation, and allylation, as well as late-stage functionalization of derivatized drug molecules. Notably, alkylboronic acids can be selectively activated in the presence of a boronic pinacol ester.

SUBMITTER: Yue F

PROVIDER: S-EPMC9683010 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

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Alkylboronic acids as alkylating agents: photoredox-catalyzed alkylation reactions assisted by K3PO4.

Yue Fuyang F Ma Henan H Song Hongjian H Liu Yuxiu Y Dong Jianyang J Wang Qingmin Q

Chemical science 20221101 45

Despite the ubiquity of alkylboronic acids in organic synthesis, their utility as alkyl radical precursors in visible-light-induced photocatalytic reactions is limited by their high oxidation potentials. In this study, we demonstrated that an inorganophosphorus compound can modulate the oxidation potentials of alkylboronic acids so that they can act as alkyl radical precursors. We propose a mechanism based on the results of fluorescence quenching experiments, electrochemical experiments, 11 ...[more]

PMID: 36507180

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