27 Penostatin Bの全合成(口頭発表の部)

抄録

Penostatins A - I were isolated from Penicillium sp. OUPS-79 separated from a marine alga by Numata. They exhibited significant cytotoxicity against P388 cells. Because of the intriguing structural features, biological profiles and less availability, they represent attracting targets for total synthesis. Although a report on the synthesis of 5-deoxy-penostatin A has only been published, total synthesis has never been reported so far. Here, we report the first total synthesis of penostatin B (2). The key features of the synthesis are 1) Lewis acid-mediated highly diastereoselective introduction of an alkenyl side chain to the dihydropyran ring, 2) successful application of a relay ring-closing metathesis (RRCM) to the construction of the dihydropyranone ring, and 3) the use of a group and face selective Pauson-Khand reaction for the diastereoselective construction of the bicyclic skeleton.