Abstract:
The efficient synthesis of several spirocyclic imines of similar structure to that present in the shellfish toxins, the spirolides and gymnodimine, is described. The key steps involved double α-alkylation of simple lactam starting materials, Grubbs’ ring closing metathesis of the resultant bis-alkylated lactams and LiEt3BH reduction of the TEOC protected lactams to imines.