Redox Inversion: A Radical Analogue of Umpolung Reactivity for Base- and Metal-Free Catalytic C(sp <sup>3</sup> )–C(sp <sup>3</sup> ) Coupling
Chris M. Seong, Annabel Q. Ansel, Courtney C. Roberts
Abstract
The construction of alkyl–alkyl bonds is a powerful tool in organic synthesis. Redox inversion, defined as switching the donor/acceptor profile of a functional group to its acceptor/donor profile, is used for C(sp 3 )–C(sp 3 ) coupling. We report a photocatalytic coupling of carboxylic acids to form bibenzyls through a radical–radical coupling. Mechanistic insight is gained through control reactions. This unexplored redox-opposite relationship between a carboxylic acid and its redox-active ester is implemented in catalysis.
Topics & Concepts
UmpolungRedoxChemistryAcceptorCatalysisAlkylCoupling reactionReactivity (psychology)PhotochemistryCarboxylic acidPolymer chemistryOrganic chemistryMedicinePhysicsPathologyAlternative medicineNucleophileCondensed matter physicsRadical Photochemical ReactionsCatalytic C–H Functionalization MethodsCatalytic Cross-Coupling Reactions