Synthetic studies on kinamycin antibiotics: elaboration of a highly oxygenated D ring

The synthesis of the model compound of kinamycin antibiotics, which possesses correct relative configurations at C1–C4 on the D ring, is reported in detail. The key steps involved a Diels–Alder reaction of indenone (12) and a Danishefsky-type diene (13), and stereoselective construction of a tetraoxygenated D ring.