Synthetic studies on kinamycin antibiotics:synthesis of a trioxygenated benz[f]indenone and its diels-alder reaction to a kinamycin skeleton

摘要

A benzo[b]fluorene skeleton such as 10,a basic four-ring system in the revised diazo strctures 3 of kinamycin antibiotics,was synthesized by Diels-Alder reaction between dienophile 4,7,8-trioxygenated 1H-benz[f]indent-1-one 11 and Danishefsky-type diene7.The indenone 11 was prepared by deoxygenation of 2,3-dihydro-1H-benz[f]inden-1-one 12 with the inexpensive 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (IBX)fter modification of the know protocol.Indenone 12 in turn was obtained from naphthalene-1,5-diol (14)via at intramolecular Friedel-Crafts cyclization of Naphthalene-2-propanoic acid 13 ad a key step.