Abstract
Two successful syntheses of cytochalasins accomplished at Columbia University are described in a context of general problems associated with the synthesis of this class of compounds. The key features of the syntheses involve a regio- and stereoselective Diels-Alder reaction of an enol lactam, e. g., 57, and a triene, e. g., 49, followed by stereocontrolled formation of 6, 7-epoxide (to cytochalasin F, 3), which is then transformed to Δ6 (12) -allylic alcohol (to cytochalasin B, 2). The first synthesis solved these fundamental structural problems and the second streamlined the overall strategy by using a macrocyclic internal Diels-Alder reaction and some new phosphorus and aluminium reagents.
