Partial synthesis of 6β-sesquiterpenolides from 6α-sesquiterpenolides
作者:José L. Bretón、Juan J. Cejudo、Andrés García-Granados、Andrés Parra、Francisco Rivas
DOI:10.1016/s0040-4039(00)74823-4
日期:1992.6
Chemical means were used to achieve the epimerization at C-6 of 6α-eudesmanolides, with several functionalizations, to 7β-eudesmanolides. The process consists of the LiAlH4 reduction of a 6α-lactone, selective acetylation of the hydroxymethylene group at C-12, oxidation and reduction at C-6 to epimerize this carbon, deacetylation at C-12 and final formation of a 6β-lactone with RuH2(Ph3P)4. The whole
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