Reactions of (R) and (S)-1,1,2-triphenyl-1,2-ethandiols induced by aminium salts and protic acids. Solvent effects

Article abstract of DOI:10.1016/S0040-4020(97)00689-3

(R) and (S) 1,1,2-triphenyl-1,2-ethandiols (1a) and (1b), upon treatment of their dichloromethane solutions with catalytic amounts of aminium salt cation radicals afforded mixtures of the corresponding pinacolones (Ph₃CCHO, 90%) (2), Ph₂CHCOPh, 10%) (3), whereas similar reactions, carried out in acetonitrile, led to consistent amounts of both pinacolones, together with benzophenone (4), benzaldehyde (5) (minor amounts), and new products (30%), fully characterized as (R) and (S) 4,4,5-triphenyl-2-methyloxazolines (7a,b). The formation of these latter was selectively inhibited in the aminium salt induced reactions, modified by 2,6-di-tert-butylpyridine (DBP).