Partial synthesis of 6β-eudesmanolides and 6β-guaianolides from 6α-eudesmanolides: Synthesis of analogues of artepaulin, colartin and tannunolide D
作者:José L. Bretón、Juan J. Cejudo、Andrés García-Granados、Andrés Parra、Francisco Rivas
DOI:10.1016/s0040-4020(01)87003-4
日期:1994.2
The epimerization process consists of the LiA1H4 reduction of a 6α-lactone, selective protection of the hydroxymethylene group at C-12, oxidation and reduction at C-6 to epimerize this carbon, deprotection at C-12 and finally, lactonization with tetrapropylammonium perruthenate (TPAP) and 4-methylmorpholine N-oxide (NMO) in yields over 80%. The rearrangement of 1β-hydroxy-6β-colartin allow us to obtain
Chemical, enzymatic and microbiological synthesis of 8,12-eudesmanolides: Synthesis of sivasinolide and yomogin analogues
作者:Andrés García-Granados、Andrés Parra、Yolanda Simeó、Antonio L. Extremera
DOI:10.1016/s0040-4020(98)00893-x
日期:1998.11
chemical, enzymatic and microbiological means. Catalytic hydrogenation of α-santonin gave a mixture of hexahydro derivatives, which were sequentially isolated by lipase-catalysed selective acylation. Reduction of the 6α-lactone ring, chemical acetylation and enzymatic selective deacetylation gave an eudesmane with a hydroxymethylene group at C-12, which was hydroxylated at C-8 by Rhizopus nigricans. Finally