Photochemical Nickel-Catalyzed C–H Arylation: Synthetic Scope and Mechanistic Investigations

Autor: John C. Tellis, Drew R. Heitz, Gary A. Molander
Rok vydání: 2016
Předmět:
Zdroj: Journal of the American Chemical Society
ISSN: 1520-5126
0002-7863
Popis: An iridium photocatalyst and visible light facilitate a room temperature, nickel-catalyzed coupling of (hetero)aryl bromides with activated α-heterosubstituted or benzylic C(sp3)–H bonds. Mechanistic investigations on this unprecedented transformation have uncovered the possibility of an unexpected mechanism hypothesized to involve a Ni–Br homolysis event from an excited-state nickel complex. The resultant bromine radical is thought to abstract weak C(sp3)–H bonds to generate reactive alkyl radicals that can be engaged in Ni-catalyzed arylation. Evidence suggests that the iridium photocatalyst facilitates nickel excitation and bromine radical generation via triplet–triplet energy transfer.
Databáze: OpenAIRE