Synthesis of β-hydroxypiperidine alkaloids by anodic oxidation of carbamates and hydroboration

Abstract

The β-hydroxypiperidine alkaloids (±)-pseudoconhydrine, (±)-N-methylpseudoconhydrine, (-)-5-hydroxysedamine, and (+)-sedacryptine were synthesized. Successive functionalization of the piperidine ring via anodic methoxylation allowed the regio- and stereoselective introduction of the substituents. The α and α' substituents were introduced by application of the sequence elimination - nucleophilic addition from 2- or 2,5-substituted 6-methoxycarbamates. Hydroboration - oxidation of enecarbamates, obtained by elimination of methanol from α-methoxycarbamates, allowed the introduction of the β-hydroxy function.