Etude par résonance magnétique nucléaire à température variable de composés apparentés au méthylènecyclohexane

Abstract

Spectral modifications have been observed in the n.m.r. spectra of difluoromethylenecyclohexane, isopropylidenecyclohexane, and dichloromethylenecyclohexane. The free energy barriers for conformational interconversion in these compounds have been estimated and are discossed.

Nuclear magnetic resonance investigation of the conformational dynamic properties of benzocycloheptenones and related compounds

“…In fact it has been shown (40) that torsional energy accounts for a !arge part of the energy difference between the chair and the inversion transition state of cyclohexane. The variation in AG' values of the sixmembered cyclic compounds listed in Table 1 was consequently rationalized convincingly in terms of the ease of rotation of the bonds adjacent to the .sp2 carbon (24,25). Table 1 reveals a very similar trend for both the six-and seven-membered cyclic compounds listed, such that it is Jery tempting to suggest that inversion in the second series of compounds also proceeds t h r o~g h a pathway involving appreciable rotation cf the bonds adjacent to the sp2 carbon atom and consequently that the chair conformation of these compounds inter- Furthermore, the higher AG* value determined for 4 compared to 5 is consistent with a C(5) wag.…”

Spiro[1,2]oxaphosphetanes of Nonstabilized and Semistabilized Phosphorus Ylide Derivatives: Synthesis and Kinetic and Computational Study of Their Thermolysis

“…778–66–5) are commercial. Compounds 10b , 10c , Z- 10e , , 10d ( =10p ), , E- 10e , , 10j , 10k , 10l , Z - 10n , 10o , and 11 have been described previously.…”