Unusually large deuterium isotope effects on one‐bond 13C, 1H coupling constants in trans‐stilbene challenged

Abstract The reported apparent large decrease in 1J(C‐α, H‐α) by 1.75±0.20 Hz on replacement of one of the olefinic protons by deuterium in trans‐stilbene is due to improper first‐order analysis of the 1H‐coupled 13C spectrum of the parent compound. Consequently, the implied conformational difference between trans‐stilbene and α‐deuterio‐trans‐stilbene, which was used to explain the result, is not substantiated.