Molecular modeling studies of the reactions of phenoxy radical dimers: pathways to dibenzofurans.

摘要: The B3LYP hybrid density functional computational technique was applied to describe the sequence of phenoxy radicals coupling reactions leading formation dibenzofurans. Reaction kinetic parameters were estimated for key reactions. Aromatization bis-keto dimers followed by intermediate dehydration or dehydroxylation demonstrated be a strongly stereoselective process. While S,S-diastereomer ortho-C//ortho-C keto dimer forms (o,o‘)-dihydroxybiphenyl, known dibenzofuran intermediate, via inter-ring hydrogen transfer reaction, less stable R,S-stereoisomer can easily transformed into another 5-hydroxyl-4,5-cyclohexadiene-2,3-benzofuran that provides an energetically more favorable pathway dibenzofuran. possible channels radical-chain processes convert these intermediates and polychlorinated dibenzofurans are discussed.