Stereochemistry of Quinolizidines. II. Carbon-13 Magnetic Resonance Spectra of N-Methylquinolizidinium Ions

Abstract

The carbon magnetic resonance spectra of trans-(I) and cis-N-methylquinolizidinium ion (II) were examined in relation to the stereochemistry of these compounds. Ring inversion of the cis-N-methylquinolizidinium ion was observed in variable temperature experiments and results afforded ΔGc^≠=13.7 kcal/mole. The observed carbon chemical shift difference between I and II was compared with that estimated empirically, and shown to be a measure of the stereochemical difference between the trans-and cis-forms of the quinolizidine nucleus.