Work

Regiocontrolled hydrobromination of unactivated alkenes via direct and chain-walking pathways

Year: 2025

Type: article

Abstract: The development of regioselective methods for C(sp 3 )─Br bond formation in unactivated alkenes remains a fundamental challenge in organic synthesis. Herein, we report a nickel hydride–catalyzed method that enables regiocontrolled hydrobromination of both terminal and internal alkenes through strategic deployment of an N -fluoropyridinium oxidant. The method features two complementary approaches: direct hydrobromination of alkenes with high proximal selectivity and a chain-walking strategy that enables switchable site-selective functionalization in extended alkyl chains. Notably, temperature-controlled reaction parameters enable regiodivergent access to β- or γ-brominated products from identical alkenes with excellent selectivity. The protocol demonstrates broad functional group tolerance and enables late-stage functionalization of pharmaceuticals. Mechanistic studies, including deuterium labeling, radical clock experiments, and density functional theory calculations, revealed a radical-mediated pathway featuring temperature-dependent regioselectivity in the chain-walking process. This unified method provides a versatile platform to access diverse alkyl bromides and offers fundamental insights into selective C─Br bond construction through direct and chain-walking pathways.

Source: Science Advances

DOI: 10.1126/sciadv.adz7088

Authors: Minseok Kim, Seunghoon Han, Changseok Lee, Sungwoo Hong

Institutions: Korea Advanced Institute of Science and Technology, Institute for Basic Science

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,500

Funder: Institute for Basic Science