Substituted .gamma.-lactones with vicinal hydrogen atoms. Conformational study by MM2 calculations and coupling constant analysis (original) (raw)

1993, The Journal of Organic Chemistry

The conformational analysis of substituted y-lactones with vicinal hydrogen atoms is carried out by the MM2/3JHH tandem. The agreement between experimentally available and calculated data is globally correct (rms = 1.16 Hz). A general preference for a hydroxyl group to occupy the equatorial position if it is on C-2 or the axial position if it is on C-3 or C-4 is observed as a consequence of the presence of H bond or of the gauche effect, respectively. (1) Tomioka, K.; Cho, Y.-S.; Sato, F.; Koga, K. J. Org. Chem. 1988,53, 4094. (2) As examplee see: (a) Vekemaus, J. A. M.; Chittenden, €2. G. F. J. Org. Chem. 1987,52,1093 and references cited therein. (b) Ortufio, R. M.; Bigorra, J.; Font, J. Tetrahedron 1988, 44, 5139. (c) Corbera, J.; Font, J.; Modvatje, M.; Ortufio, R. M.; SAnchez-Ferrando, F. J. Org.