STEREOSELECTIVE CONSTRUCTION OF THE DITERPENE PART OF INDOLE ALKALOIDS, RADARINS, BY WAY OF INTRAMOLECULAR DIELS-ALDER REACTION

摘要

The tricyclic diterpene part of the indole alkaloids, radarins A-D (1-4), was synthesized in a highly stereoselective manner by the exploitation of an intramolecular Diels-Alder reaction. (+/-)-5,6-Dimethyl-2,3,4,4a,5,6,7,8-octahydro-2-oxo-5-vinylnaphthalene (7) was converted into trienes 28 and 29, possessing (1E,3E)- and (1E,3Z)-4-(phenylthio)butadiene moieties. Intramolecular [4 + 2] cycloadditions of 28 and 29 yielded tricyclic 32 selectively, producing the ABC carbon skeleton of radarins. [References: 25]