Work

Photocatalytic C–I Borylation via Halogen Bond-Enabled Electron Transfer: A Strategy for Generating Aryl Radicals from Haloarenes

Year: 2025

Type: article

Abstract: We report the development of triarylphenol-based photocatalysts that promote C-I bond borylation via halogen bonding (XB) interactions under visible-light irradiation. Traditional phenol system reactions often suffer from phenoxyl radical instability, limiting their catalytic utility. To overcome this issue, we designed sterically and electronically tuned triarylphenols that stabilize radical intermediates while maintaining high photoreactivity. Systematic evaluation revealed that 2,4,6-triphenylphenol efficiently facilitates photoinduced electron transfer (PET) and suppresses undesired side reactions such as phenol decomposition. The optimized reaction conditions enabled a broad substrate scope, showing efficient arylboronic ester formation. Density functional theory calculations confirmed the formation of XB complexes with charge-transfer character, providing mechanistic support for the PET pathway. This work shows the potential of rationally designed phenols as XB acceptors and offers a sustainable approach for C-I bond functionalization.

Source: Chemical and Pharmaceutical Bulletin

DOI: 10.1248/cpb.c25-00375

Authors: Eiji Yamaguchi, Tomohiro Yasuda, Akichika Itoh

Institutions: Gifu Pharmaceutical University, Gifu University

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: diamond

Funders: Ministry of Education, Culture, Sports, Science and Technology, Inamori Foundation, Hokkaido University, Japan Society for the Promotion of Science

Award: Development of Control of Electron Transfer in Excited States of Anionic Molecules to Photocatalytic Reactions