Photoinduced metal-free borylation of aryl halides catalysed by an in situ formed donor–acceptor complex. Issue 17 (11th April 2022)

• Record Type: Journal Article
• Authors: Li, Manhong; Liu, Siqi; Bao, Haoshi; Li, Qini; Deng, Yi-Hui; Sun, Tian-Yu; Wang, Leifeng
• Is Part Of: Chemical science. Volume 13:Issue 17(2022)
• Page Start: 4909
• Page End: 4914
• Publication Date: 2022-04-11
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2sc00552b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : We reported a facile metal-free conversion of aryl halides to the corresponding boronic esters catalysed by an in situ formed donor–acceptor complex. A two-step one-pot method was also developed for site selective aromatic C–H bond borylation. Abstract : Organoboron compounds are very important building blocks which can be applied in medicinal, biological and industrial fields. However, direct borylation in a metal free manner has been very rarely reported. Herein, we described the successful direct borylation of haloarenes under mild, operationally simple, catalyst-free conditions, promoted by irradiation with visible light. Mechanistic experiments and computational investigations indicate the formation of an excited donor–acceptor complex with a −3.12 V reduction potential, which is a highly active reductant and can facilitate single-electron-transfer (SET) with aryl halides to produce aryl radical intermediates. A two-step one-pot method was developed for site selective aromatic C–H bond borylation. The protocol's good functional group tolerance enables the functionalization of a variety of biologically relevant compounds, representing a new application of aryl radicals merged with photochemistry.