SmI2-mediated couplings of α-amino acid derivatives. Formal synthesis of (-)-pumiliotoxin 251D and (±)-epiquinamide.

The coupling between cyclic and acyclic α-amino acid derivatives and methyl acrylate, mediated by samarium diiodide, is described. The method constitutes a powerful tool to construct indolizidine, quinolizidine, and piperidine systems in a straightforward two-step fashion. The formal synthesis of (-)-pumiliotoxin 251D and (±)-epiquinamide is achieved after two or three steps from these amino acid derivatives.