Structures of diverpenoids grayanotoxin XV, leucothol A and B have been determined respectively as 2, 5 and 7 by X-ray crystallographic analyses. Grayanovoxin XIV and leucothol C have been characterized as 1 and monoanhydroleucothol B (8) respectively by chemical means. Grayanotoxin I, II and III have been degraded to a tricyclic compound 19 by the route outlined in Scheme 1. Partial synthesis of grayanotoxin II from 19 has been achieved through the sequence of reactions given in Scheme 2.
