A General Strategy for Aliphatic C−H Functionalization Enabled by Organic Photoredox Catalysis
K. A. Margrey, W. L. Czaplyski, D. A. Nicewicz* and E. J. Alexanian*
J. Am. Chem. Soc. ASAP
https://pubs.acs.org/doi/pdf/10.1021/jacs.8b00592
Abstract:
Synthetic transformations that functionalize unactivated aliphatic C−H bonds in an intermolecular fashion offer unique strategies for the synthesis and late-stage derivatization of complex molecules. Herein wereport a general approach to the intermolecular function-alization of aliphatic C−H bonds using an acridinium photoredox catalyst and phosphate salt under blue LED irradiation. This strategy encompasses a range of valuable C−H transformations, including the direct conversions of a C−H bond to C−N, C−F, C−Br, C−Cl, C−S, and C−C bonds, in all cases using the alkane substrate as the limiting reagent. Detailed mechanistic studies are consistent with the intermediacy of a putative oxygen-centered radical as the hydrogen atom-abstracting species in these processes.
