Synthesis of the tricyclic nucleus of the alkaloid stemofoline: X-ray crystal structure of (4RS,5RS,7SR,10RS)-10-butyl-5-hydroxy-1-azatricyclo[5.3.0.0]decan-2-one
Abstract
The tricyclic lactams 20 and 21 have been synthesized using iminium ion cyclisations and formation of the third ring via halogen metal exchange; oxidation of the lactam 22 using lead(IV) acetate gave the tetracyclic ether 27 regioselectively.