Development of new methods for generation of radical species by one-electron oxidation with metallic oxidants toward construction of carbon skeletons

By oxidation of beta-keto acids, cyclopropanols, and acyl chromate complexes with tris(2-pyridinecarboxylato)manganese(III) (Mn(pic)(3)), alpha-keto, beta-keto, and alkyl radicals are generated respectively, which react with olefinic compounds to afford intermolecular addition products in good yield. On the other hand, the cation radicals can be generated from alpha-stannylalkyl sulfides, alpha-stannylalkyl amine derivatives, and alpha-stannyl carboxylic eaters by oxidation with ammonium hexanitratocerate(IV) (CAN). These cation radicals of stannyl compounds readily cleave into carbocation or radical species, which are utilized as reactive intermediates for carbon-carbon bond formation.