Radical Reactions

The chapter focuses on compilation of thermodynamic and kinetic parameters of radicals, including radical stability energy, radical lifetime, substituent constant, and electrophilic index, along with a discussion of their relevance to radical stability. The unsymmetrical dimerization of triphenylmethyl and diphenylaminyl radicals corresponds to single electron transfer from the atom to the benzene ring and is governed by the Coulomb interaction between the effective charges on the reacting atoms. The chapter discusses the use of difluoromethyldiazomethane as a building block for difluoromethylation of organic compounds. Copper-catalyzed Chan-Lam coupling of sodium aryl sulfinates and organoboron compounds provides diaryl thioethers. Carboxylate precursors are used for the single electron transfer reduction of aryl halides and sulfonamides. A catalyst-free electrochemical method uses direct anodic oxidation of the strained cyclopropanes and butanes. The electrochemical route for the synthesis of C(3)-sulfonated benzothiophenes proceeds by tandem radical addition-cyclization.