STUDIES DIRECTED TOWARD THE TOTAL SYNTHESIS OF TETRONOLIDE .1. AN ENANTIOSELECTIVE SYNTHESIS OF THE OCTAHYDRONAPHTHALENE UNIT

An efficient enantioselective route to the octahydronaphthalene unit present in tetronolide (1), the stereochemically complex aglycone common to the tetrocarcins, a novel group of antitumor substances, is described. The sequence employs the intramolecular Diels-Alder reaction to control the relative stereochemistry present on the trans decalin ring system, and incorporates a masked acylating agent which should permit coupling of the two key fragments 2 and 3 as demonstrated by reaction of pentaene 4 with methanol and a model alpha-hydroxy ester.