Studies on the synthesis of aphidicolin. Preparation of aromatic precursors for spirocyclic dienone formation
Abstract
Novel syntheses of the alkenediones (12; R = Me, or CH2Ph) and the corresponding epoxides (13) are described. Attempts to cyclise these compounds to the spirocyclic dienone (4) were unsuccessful. Model studies on the phenolic keto cyano toluene-p-sulphonate (24) showed that the cyclopropane (25) was formed preferentially. A variety of related model compounds (29), (31), (32), and (37) were prepared and studied, but none could be cyclised to spirocyclic dienones.