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The Slow Rearrangement of a Sterically Hindered Nitro‐Cyclohexadienone and the Absence of Phenol Oxidation by Nitrogen Monoxide
Author(s) -
Peters Steven J.,
Blood Trisha M.,
Kassabaum Mark E.
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200901074
Subject(s) - chemistry , homolysis , isomerization , steric effects , nitro , moiety , photochemistry , medicinal chemistry , intermolecular force , phenol , carbon monoxide , hydrogen atom abstraction , nitrite , radical , stereochemistry , organic chemistry , molecule , catalysis , nitrate , alkyl
Abstract The exposure of 2,4,6‐tri‐ tert ‐butylphenol ( 1 ) in solution to NO 2 · results in the rapid formation of 2,4,6‐tri‐ tert ‐butyl‐4‐nitro‐2,5‐cyclohexadienone ( 2 ), which then undergoes a slow (ca. 3 d) rearrangement in the absence of air. The mechanism that describes this rearrangement is understood for the first time and involves the initial isomerization of 2 to form a(–ONO)‐substituted cyclohexadieneone ( 6 ). The nitrite moiety undergoes bond homolysis releasing NO · while forming an oxyl radical intermediate. An intermolecular, concerted hydrogen abstraction, which proceeds between 6 and this oxyl radical, results in the simultaneous formation of all stable products, some of which have not been previously observed. Furthermore, when 1 is exposed to NO · under anaerobic conditions, no reaction is observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)