Terminal C(sp3)-H borylation through intermolecular radical sampling

• 成果类型: Article
• 署名作者: Wang, Miao; Huang, Yahao; Hu, Peng
• 署名单位: Sun Yat Sen University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12057
• DOI: 10.1126/science.adj9258
• 发表日期: 2024-02-02
• 页码: 537-544
• 关键词: c-h bonds; stereoselective functionalization; direct arylation; alkylation; diversification; photocatalysis; hydrocarbons; activation

摘要

Hydrogen atom transfer (HAT) processes can overcome the strong bond dissociation energies (BDEs) of inert C(sp(3))-H bonds and thereby convert feedstock alkanes into value-added fine chemicals. Nevertheless, the high reactivity of HAT reagents, coupled with the small differences among various C(sp(3))-H bond strengths, renders site-selective transformations of straight-chain alkanes a great challenge. Here, we present a photocatalytic intermolecular radical sampling process for the iron-catalyzed borylation of terminal C(sp(3))-H bonds in substrates with small steric hindrance, including unbranched alkanes. Mechanistic investigations have revealed that the reaction proceeds through a reversible HAT process, followed by a selective borylation of carbon radicals. A boron-sulfoxide complex may contribute to the high terminal regioselectivity observed.