Reaction of Benzopinacol with the 4-Nitropyridine N-Oxide-SbCl₅ (1 : 1) complex

Abstract

1, 2, 2, 2-Tetraphenylethanone (benzopinacolone) was obtained quantitatively by reaction of 1, 1, 2, 2-tetraphenyl-1, 2-ethanediol (benzopinacol) with the 4-nitropyridine N-oxide SbCl₅ (1 : 1) complex (Complex A). Benzopinacolone was also obtained along with a small amount of tetraphenylethylene oxide from benzopinacol using pyridine N-oxide-SbCl₅ (1 : 1) (Complex C) and 4-methylpyridine N-oxide-SbCl₅ (1 : 1) complex (Complex B). The Pinacol rearrangement of benzopinacol using α-OSbCl₄ pyridines followed the order :
γ-NO₂ α-OSbCl₄ pyridine>>γ-CH₃ α-OSbCl₄ pyridine≥α-OSbCl₄ pyridine