AbstractThe 13C NMR spectra of a series of 6,7‐benzomorphan derivatives variously substituted at C‐5 and C‐9 by methyl and at C‐3 by cyano, alkyl and aralkyl groups, together with certain 3‐cyano, 3‐allyl or benzyl congeners, are reported and chemical shift data analysed in terms of the configuration of isomeric pairs and compounds isolated as single diastereoisomers. Special attention is given to the consequences of γ‐shielding interactions, the effects of the nitrogen lone‐pair orbital and anisotropic shielding by the aromatic region of the molecule. Deductions of stereochemistry are supported by 1H NMR data and the NMR features of the corresponding methiodide salts.
AbstractThe 13C NMR spectra of a series of 6,7‐benzomorphan derivatives variously substituted at C‐5 and C‐9 by methyl and at C‐3 by cyano, alkyl and aralkyl groups, together with certain 3‐cyano, 3‐allyl or benzyl congeners, are reported and chemical shift data analysed in terms of the configuration of isomeric pairs and compounds isolated as single diastereoisomers. Special attention is given to the consequences of γ‐shielding interactions, the effects of the nitrogen lone‐pair orbital and anisotropic shielding by the aromatic region of the molecule. Deductions of stereochemistry are supported by 1H NMR data and the NMR features of the corresponding methiodide salts.