A formal total synthesis of (+)-tetrononlide, the aglycon of the tetrocarcins: enantio- and diastereoselective syntheses of the octahydronaphthalene (bottom-half) and spirotetronate (top-half) fragments

摘要

A formal total synthesis of (+)-tetronolide, the aglycon of the tetrocarcins, has been achieved by virtue of the development of highly diastereo- and enantioselective syntheses of the bottom- and top-half fragments 4 and 5 reported herein. Theses fragments previously served as key intermediates top-half fragments 4 and 5 reported herein. These fragments previously served as key intermediates in Yoshii's pioneering total synthesis of (+)-tetronolide. The synthesis of the bottom-half octahydronaphethalene unit 4 features the intramolecular Diels-Alder reaction of tetraenal 20 and proceeds in 17 steps and 5-6/100 yield from D-glyceraldehyde pentylidene acetal 8.