Studies in the synthesis of C‐ring bridged morphinans 3—¹³C NMR analysis of some simple and complex bicyclooctane derivatives

The ¹³C NMR spectra of eight novel derivatives of bicyclo[2.2.2]‐ and ‐[3.2.1]octane have been recorded and analysed. These compounds were isolated and characterized as intermediates in the synthesis of a unique derivative of 1,2,3,3a,11b,11c‐hexahydroaporphine. Carbon chemical shift assignments of the molecules under investigation were based on ¹³C NMR theory including splitting patterns, differences in chemical shift values of carbons α and β to amino nitrogens in their protonated and non‐protonated forms, and through the anticipated shielding effects of γ‐syn and γ‐anti heteroatoms. This latter method of analysis was particularly useful in assigning the chemical shift values of carbons in the bicyclooctane region of the simpler molecules.