The Nuclear Magnetic Resonance Spectra and Stereochemistry of Substituted Bornanes

Base-catalyzed enolization of 2,5-norbornanediones. Evidence for homoenolic assistance

“…5c) there is a further sharpening of the exo-C(5)-H signal to a width at half-height of 8.5 Hz. This result is consistent with the removal of a 2.5 Hz coupling, which is expected for the loss of a vicinal exo-endo trans coupling in the [2.2.1] system (14,15). Clearly, as in the case of the monoketones, ex0 exchange is preferred.…”

Synthesis and characterization of 2-substituted bornane pharmacophores for novel cannabinergic ligands

“…The chemical shift differences and coupling patterns of the benzylic protons of 6 and 7 were in agreement with reported values for bornyl and isobornyl analogs. 22 The H-2 exo proton of 6 was downfield relative to the H-2 endo of 7 . Also, we observed 4 J -coupling 23 of the H-2 exo benzylic proton of 5-bornyl-1,3-dimethoxybenzene ( 6 ) that was confirmed by COSY spectroscopy to be coupling to the coplanar H-6 exo .…”

Dioxa-1,3-bishomopentaprismane: synthesis and transformations

“…* The 'H NMR spectrum of the resulting carboxylic acid product was consistent in all respects to a literatwe spectrum of bornanecarboxylic acid (3). 5 No evidence for the formation of isobornanecarboxylic acid (4) was present. The presence of any 4 would have been detected in the NMR spectrum by a triplet due to the a-methine hydrogen of 4 at 6 2.34.6 The a-methine hydrogen in 3 appears as a distorted triplet farther downfield at 6 2.70.…”