A novel cascade reaction to form indolizidine and quinolizidine alkaloids: Facile syntheses of (±)-epilupinine and (±)-tashiromine

ORGN 124

Stephen F. Martin and Shawn M. Amorde. Department of Chemistry & Biochemistry, The University of Texas, 1 University Station A5300, Austin, TX 78712-0165
A new cascade reaction forming aza-[m.n.0]-bicyclic alkaloids from relatively simple aldehydes and amines is reported. This strategy takes advantage of the facile formation and ambident nature of imines. Intramolecular formation of an iminium ion and subsequent alkylation forms four bonds in one step with excellent selectivity. This method is showcased by the total syntheses of (±)-epilupinine and (±)-tashiromine in two steps from known compounds.