New syntheses of (±)-lamprolobine and (±)-epilamprolobine

Article abstract of DOI:10.1016/S0040-4020(01)89049-9

(±)-Lamprolobine 1 and (±)-epilamprolobine 4 were prepared by a route featuring sulphide contraction of thiolactam 7 with bromoacetonitrile to give vinylogous cyanamide 8, reduction and ring closure to the unsaturated quinolizidine 11, and selective reduction of the latter to set up appropriate stereochemistry for the target alkaloids.