Synthesis and absolute configuration of 2-(12′-aminotridecyl)-pyrrolidine, a defensive alkaloid from the Mexican bean beetle, Epilachna varivestis

The synthesis of 2-(12′-aminotridecyl)-pyrrolidine (1), a defensive alkaloid recently isolated from the Mexican bean beetle, Epilachna varivestis, is described. The (2S,12′R) configuration is assigned to this alkaloid by comparing the ¹H NMR spectrum of its (S)-MTPA derivative with that of (R)-and (S)-MTPA [α-methoxy-α-(trifluoromethyl)phenylacetyl] derivatives of the synthetic sample. These results suggest that the seventeen carbon skeleton of 1 is acetate rather than proline derived.