A mild oxidative deamination reaction of tetrahydroanabasine O-methyloxime 17 is described, making use of an o-quinone that is based on topaquinone (TPQ, 11), the cofactor that is present in copper-containing amine oxidases, In situ ring closure of the oxidation product produced double-functionalized quinolizidine 5, containing an enamine functionality with excellent reactivity, From this quinolizidine 5 a variety of biogenetically related lupin alkaloids were prepared: lupinine (7) and aminolupinane (8) via reductive sequences and sparteine (9) via a condensation reaction with dehydropiperidine 1. The configurationally more favorable trans isomers epilupinine (25) and beta-isosparteine (10) were formed when more drastic reaction conditions were used for oxime hydrolysis, Anabasine (4) and a new 5-piperidylanabasine derivative 6 were formed by an unexpected acid catalyzed ring transformation reaction, whereby the pyridine ring was formed via oxime-induced aromatization. The stereochemistry of the reaction products and the biogenetic implications are discussed.