Stereoselective synthesis of 4 alpha-hydroxy-8,12-guaianolides from santonin |
| |
Authors: | Blay Bargues Cardona Collado Garcia Munoz Pedro |
| |
Institution: | Departamento de Quimica Organica, Facultad de Quimica, Universitat de Valencia, Spain. |
| |
Abstract: | Hydroxyester 2, easily obtained from santonin (1), has been transformed into 10 alpha-hydroxyguai-3-en-8,12-olide 6, a good intermediate for the synthesis of natural 8,12-guaianolides. Compound 6 was obtained from 2 by photochemical rearrangement of its acetyl derivative 7, stereoselective hydrogenation on Pd/C, reduction, regioselective elimination, hydrolysis, and lactonization. The synthesis of the natural guaianolides 3-5 was carried out in two sequences in which the regioselective elimination of a hydroxyl group at C10 with triflic anhydride or SOCl2 to afford, respectively, the endo or exo double bond on C10 and the regioselective opening of the C3-C4 alpha-epoxide were the key steps. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|