A case of chain propagation: α-aminoalkyl radicals as initiators for aryl radical chemistry.

From Europe PMC via Jisc Publications RouterHistory: ppub 2020-10-01, epub 2020-10-20Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; Grant(s): EP/P004997/1Funder: European Research Council; Grant(s): 758427The generation of aryl radicals from the corresponding halides by redox chemistry is generally considered a difficult task due to their highly negative reduction potentials. Here we demonstrate that α-aminoalkyl radicals can be used as both initiators and chain-carriers for the radical coupling of aryl halides with pyrrole derivatives, a transformation often employed to evaluate new highly reducing photocatalysts. This mode of reactivity obviates for the use of strong reducing species and was also competent in the formation of sp2 C-P bonds. Mechanistic studies have delineated some of the key features operating that trigger aryl radical generation and also propagate the chain process

Synthesis of quaternary aryl phosphonium salts: photoredox-mediated phosphine arylation

We report a synthesis method for the construction of quaternary aryl phoshonium salts at ambient temperature. The regiospecific reaction invovles the coupling of phosphines with aryl radicals derived from diaryliodonium salts under photoredox conditions