a single-electron reducing agent under photoirradiation from a blue light-emitting diode, in the presence of appropriate electron acceptors, and the resulting sulfur-centered radical species undergoes hydrogenatomabstraction. This dual-role catalysis by TBA enables regioselectivie Cα–H arylation of benzylamines, benzyl alcohols, and ethers, as well as dihydroimidazoles, with cyano(hetero)arenes in
A catalytic amount of a sterically and electronically tuned diarylsulfonamide promoted allylic and benzylic C–H arylations in cooperation with a visible light photoredox catalyst. This is the first example of the catalytic use of a sulfonamidyl radical to promote the hydrogen atom transfer process.
A General Strategy for Organocatalytic Activation of C–H Bonds via Photoredox Catalysis: Direct Arylation of Benzylic Ethers
作者:Katrine Qvortrup、Danica A. Rankic、David W. C. MacMillan
DOI:10.1021/ja411596q
日期:2014.1.15
Direct C-H functionalization and arylation of benzyl ethers has been accomplished via photoredox organocatalysis. The productive merger of a thiol catalyst and a commercially available iridium photoredox catalyst in the presence of household light directly affords benzylic arylation products in good to excellent yield. The utility of this methodology is further demonstrated in direct arylation of 2,5-dihydrofuran to form a single regioisomer.