Nickel/photoredox-catalyzed boryl radical relay dual arylation/acylation of alkenes
摘要
Herein, we report a novel dual nickel/photoredox catalytic system for alkene diarylation and diacylation, centered around a unique boron-mediated radical relay mechanism. The key steps of this process involve the efficient cleavage of B–H bonds and the selective activation of inert C(sp2)–X bonds. Specifically, photocatalytically generated bromine radicals first undergo hydrogen atom transfer (HAT) with amine-boranes, cleaving the B–H bond. The resulting boryl radicals then serve as potent activators to engage inert aryl bromides or acyl chlorides via halogen atom transfer (XAT), effectively breaking the C(sp2)–X bonds and releasing key aryl and acyl radicals. These carbon-centered radicals subsequently add to alkenes, and the resulting adducts are efficiently captured by nickel species and funneled into a downstream nickel catalytic cycle to accomplish alkene difunctionalization. This strategy is distinguished by its broad substrate compatibility, excellent chemo-selectivity, capability for late-stage functionalization of drug molecules, and the use of commercially available and stable reagents. It thus provides an efficient and reliable route to synthetically valuable 1,2-diaryl- and 1,2-diacyl-substituted compounds.