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Proton‐Driven Conformational Switch of a Cyclohexyl Skeleton Coupled with NH···O Hydrogen‐Bond Formation
Author(s) -
Onoda Akira,
Haruna Hiroshi,
Yamamoto Hitoshi,
Takahashi Kazuyuki,
Kozuki Hidekazu,
Okamura Takaaki,
Ueyama Norikazu
Publication year - 2005
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.200400385
Subject(s) - chemistry , protonation , deprotonation , hydrogen bond , proton , stereochemistry , nuclear magnetic resonance spectroscopy , proton nmr , crystallography , molecule , ion , organic chemistry , physics , quantum mechanics
Abstract We report an unprecedented, proton‐drivenring transfor‐mation from a chair to a twist‐boat conformation in the doublyamide‐derived Kemp’s acid compounds r ‐1, c ‐3, c ‐5‐(CH 3 ) 3 ‐3,5‐(Ph 2 CHNHCO) 2 C 6 H 6 ‐1‐COOH ( 1 ) and (NMe 4 ){ r ‐1, c ‐3, c ‐5‐(CH 3 ) 3 ‐3,5‐(Ph 2 CHNHCO) 2 C 6 H 6 ‐1‐COO – } ( 2 ) with a protonated and deprotonated carboxyl group, respectively. Each conformation was determined by X‐ray analyses and 1 H NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)