Toward Pyridine-Heterocycle Patterns through Prins and Aza-Prins Cyclisations: Application to a Short Synthesis of (±)-Anabasine

The formation of pyridine‐containing bisheterocycles through a Prins‐type cyclisation is described. Pyridine–tetrahydropyran and pyridine–piperidine conjugates could be efficiently obtained using various carbaldehydes including dicarbaldehydes, and either homoallylic alcohols or a homoallylic amine. Selective partial or complete hydrogenation led to new bisheterocycle combinations. A two‐step sequence involving an aza‐Prins cylisation allowed us to prepare the alkaloid anabasine. The (aza)‐Prins cyclisation has been applied to several pyridine carbaldehydes, opening the way to an easy access to bisheterocycles. The method was effective for the synthesis of anabasine in two steps.