Radical C-H Arylation of Oxazoles with Aryl Iodides: dppf as an Electron-Transfer Mediator for Cs2CO3

A radical C-H arylation reaction of oxazoles with (hetero)aryl iodides using Cs2CO3 as base/electron donor and 1,1'-bis-(diphenylphosphino) ferrocene (dppf) as a catalytic SET mediator is reported. The overall reaction likely follows the general base-promoted homolytic aromatic substitution mechanism through a radical-chain pathway. DFT calculations suggest that dppf forms a complex with CsCO3-, enhancing its SET reducing ability to generate an aryl radical from Arl.