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13 C, 1 H long‐range coupling constants in configuration assignment of some trisubstituted alkenes
Author(s) -
Fischer Peter,
Schweizer Eberhard,
Langner Jörg,
Schmidt Ulrich
Publication year - 1994
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260320918
Subject(s) - chemistry , coupling constant , chemical shift , range (aeronautics) , stereochemistry , coupling (piping) , double bond , computational chemistry , crystallography , analytical chemistry (journal) , organic chemistry , physics , mechanical engineering , materials science , particle physics , engineering , composite material
Chemical shifts and long‐range 13 C, 1 H coupling constants to the two carbonyl C atoms were determined for a series of ethyl 2‐acyloxy‐2‐alkenoates. The 3 J (C,H) coupling constant across the double bond is 9.5–10.1 Hz for the E ‐ and 2.9–3.8 Hz for the Z ‐isomer. 3 J (C,H) values, therefore, may be used as a criterion for E/Z differentiation even if only one isomer is available. 13 C chemical shift data, in contrast, cannot be employed for a straightforward differentiation.