Synthesis and Stereochemistry in B/C Ring Juncture of Lactamcarbinol A, a Degradation Product of Securinine

Abstract

Cis-and trans-2-Hydroxy-2-(2-pyridyl) cyclohexaneacetic acid, (X) and (VIII), were synthesized and their stereochemistries discussed. The latter (VIII) was converted into racemic lactam-carbinol A (I), which showed the same infrared spectrum in chloroform as that of natural lactam-carbinol A obtained by degradation of securinine. The present work proved unequivocally the stereochemistries in B/C ring junctures of lactamcarbinols A (I) and B (II), and quinolizidines A (IV) and B (V), degradation products of securinine.