Synthetic studies on pseudoguaianolides. II. A total synthesis of (.+-.)-carpesiolin.

DOI Web Site

説明

A total synthesis of (±)-carpesiolin (3) is reported starting from the hydroazulenone (2), which is a key intermediate of helenanolide synthesis. For the introduction of the C6 to C8 functionalities, 2 was converted to the epoxy-alcohol (5). Its structure was confirmed by chemical and spectroscopic evidence. After construction of the γ-lactone ring, the tert-butyl protective group was removed from the ester (15) by acid-catalyzed thermolysis. However, this reaction was unexpectedly accompanied by concomitant 1, 3-acyl migration with inversion of the configuration at C4 to yield the hydroxy-ester (16), whose structure was established by analysis of its proton magnetic resonance spectrum and some chemical reactions. After manipulation of the protective group to give the tetrahydropyranyl ether (18), its conversion to (±)-carpesiolin was achieved by (i) introduction of the exo-methylene group onto the lactone ring, (ii) oxidation to the cyclopentanone (24), and (iii) deprotection of the C6 hydroxyl group.

収録刊行物

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ