title: Hyperconjugation involving strained carbon-carbon bonds. structural analysis of ester and ether derivatives and one-bond 13C-13C coupling constants of α- and β-nopinol.
abstract: σ(C-C)-σ*(C-O) interactions involving the strained carbon-carbon bonds of α- and β-nopinol, and their ester and ether derivatives have been demonstrated in the solid state using the variable oxygen probe. These hyperconjugative interactions are manifested as a strong response of the C-OR bond distance to the electron demand of the OR substituent. Although the effects upon the donor C-C bond distances are not large enough to be measurable by X-ray crystallography, they do result in systematic and measurable effects on the (13)C-(13)C one-bond coupling constants. For the donor C-C bond, coupling constants decrease, consistent with weakening of this bond, while the intervening C-C bond coupling constants increase, consistent with bond strengthening, as the electron demand of OR increases.
authors.affiliation: School of Chemistry and Bio-21 Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: Shinn Dee
authors.initials: SD
authors.lastname: Yeoh
authors.forename: Colin E
authors.initials: CE
authors.lastname: Skene
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D002247:Carbon Isotopes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004952:Esters / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory
chemical_list: D001952:Bridged-Ring Compounds; D002247:Carbon Isotopes; D004952:Esters; D004987:Ethers; C583344:nopinol; D002244:Carbon