Stereochemistry of benzo [α] quinolizidine derivatives (I-VIb) were examined from C-13 magnetic resonance chemical shifts, and C-6 and C-7 shifts of these compounds were found to be reliable as the indications of favoured conformations-trans, cis "a" or cis "b". This treatment is also available for the conformational analyses of tetrahydroproto-berberine type alkaloids.
