Lifting of the Degeneracy in Semibullvalenes by Remote and Direct Substituents: A Quantitative Study Using Variable-Temperature Carbon-13 NMR Spectroscopy

M Heubes, T Dietz, H Quast, M Seefelder…

Index: Heubes; Dietz; Quast; Seefelder; Witzel; Gadgil; Williams Journal of Organic Chemistry, 2001 , vol. 66, # 6 p. 1949 - 1960

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Citation Number: 7

Abstract

A series of six 1, 5-(ethylmethyl) semibullvalenes (1a⇋ 1a', 2⇋ 2', 3⇋ 3') and two 4 (2)- substituted semibullvalenes (4⇋ 4'), each undergoing Cope equilibria between nondegenerate valence tautomers, was investigated by carbon-13 NMR spectroscopy at a range of temperatures in several different solvents. Gompper's treatment of substituent perturbation was extended, specifically accounting for the effects of the substituents on ...