Synthesis and absolute configuration of two defensive alkaloids from the Mexican bean beetle, Epilachna varivestis

Syntheses of (2S,12'R)-2-(12'-aminotridecyl)-pyrrolidine (1) and (28,12'R)-1-(2'-hydroxyethyl)-2-(12'-aminotridecyl)-pyrrolidine (2), two defensive alkaloids recently isolated from the Mexican bean beetle, Epilachna varivestis, are described. By a comparison of ¹H NMR data of MTPA derivatives of natural alkaloid 2 with those of the synthetic standard, we confirm the (2S,12'R) configuration previously suggested for this alkaloid. Further support of these assignments was provided by the synthesis and ¹H NMR investigation of(2S,12'S)-1, (2S,12'S)-2, and their MTPA derivatives.