Total Synthesis and Biological Evaluation of (−)-9-Deoxy-englerin A
摘要:
An effective total synthesis of (-)-9-deoxy-englerin (4), an analogue of the natural guaiane sesquiterpene englerin A (1), has been achieved. The synthesis features a transannular epoxide opening to construct the 5,7-fused ring system followed by transannular ether formation with mercury(II) trifluoroacetate.
Retinoid X receptor (RXR) agonists are interesting candidates for the treatment of metabolic syndrome. 9-Cis-retinoic acid (9cRA: 1) is a natural RXR agonist, that also works as a retinoic acid receptor (RAR) agonist. This fact prompted us to study the structure–activity relationship (SAR) of RXR agonists derived from 1. Though 3 and 4, in which the cyclohexene part of 1 is replaced with bulkier hydrophobic
Scope of Enantioselective Palladium(II)-Catalyzed Aerobic Alcohol Oxidations with (−)-Sparteine
作者:Sunil K. Mandal、David R. Jensen、Jacob S. Pugsley、Matthew S. Sigman
DOI:10.1021/jo0269161
日期:2003.5.1
Evaluation of the substrate scope for Pd(II)/ (-)-sparteine catalyzed aerobic oxidative kinetic resolution of secondary alcohols is disclosed. An improved system is found with use of tert-butyl alcohol solvent in which benzylic and aliphatic alcohols as well as alcohols containing olefins are effectively oxidatively resolved. For substrates that successfully undergo oxidative kinetic resolution, k(rel) values
Pyridinium chromate-on-silica gel, and chromic acid-on-silica gel are described and evaluated as convenient off-the-shelf reagents for efficientoxidation of a variety of secondary and primary alcohols. Pyridinium chromate-on-silica gel can be safely used for the oxidation of alcohols containing acid-labile functions.
A novel photoredox catalysis for multiple functionalization of two different types of unactivatedalkenes in a single operation was reported through a conceptually new mode of annulation-alkynyl migration. A wide array of cyclopentane carboxylates were synthesized in a highly selective and functional-group-compatible manner via C-centered radical induced cascade 5-exo-trig/5-exo-dig bicyclization and
Aerobic oxidation of monoterpenic alcohols catalyzed by ruthenium hydroxide supported on silica-coated magnetic nanoparticles
作者:Vinícius V. Costa、Marcos J. Jacinto、Liane M. Rossi、Richard Landers、Elena V. Gusevskaya
DOI:10.1016/j.jcat.2011.06.014
日期:2011.8
ruthenium(III) chloride followed by treatment with sodium hydroxide to form rutheniumhydroxide species. Characterizations suggest that rutheniumhydroxide is highlydispersed on the support surface, with no ruthenium containing crystalline phases being detected. Various carbonylic monoterpenoids important for fragrance and pharmaceutical industries can be obtained in good to excellent yields starting