13C-NMR Assignments for Methyls and Quaternary Carbons of the Limonoid Obacunone

Abstract
The high field 1H and 13C resonances of obacunone were established by a series of I D and 2D NMR experiments. The 13C-NMR signals of the five tertiary methyl groups and all quatenary carbons were unambiguously assigned. The results confirm the stereochemical assignments at all stereogenic centres.