General approach to prostanes B1 by intermolecular pauson-khand reaction: Syntheses of methyl esters of prostaglandin B1 and phytoprostanes 16-B1-PhytoP and 9-L1-PhytoP
A synthetic approach to the methyl esters of Prostaglandin B1 and Phytoprostanes 16-B1-PhytoP (PPB1-I) and 9-L 1-PhytoP (PPB1-II) based on the modified Julia olefination of a formylcyclopentenone and an appropriately protected hydroxy sulfone has been developed. The cyclopentenones were efficiently prepared by intermolecular Pauson-Khand reaction of a (silyloxymethyl)alkyne. The sulfone counterpart was prepared by regioselective ring-opening of the appropriate chiral epoxides by 2-mercaptobenzothiazole. The protecting group for the alcohol functionality on the sulfone proved to be crucial. Protection as a tert-butyl ether was the best solution, giving better results than a tert-butyldimethylsilyl ether. A synthetic approach to prostanes B1 based on Julia olefination of a formylcyclopentenone and an appropriately protected hydroxy sulfone has been developed. Cyclopentenones were prepared by intermolecular Pauson-Khand reaction. Protection of the alcohol functionality of the hydroxy sulfone as a tert-butyl ether proved to be crucial. Copyright
Vazquez-Romero, Ana,Verdaguer, Xavier,Riera, Antoni
supporting information
p. 1716 - 1725
(2013/04/10)
Synthesis of prostaglandin and phytoprostane B1 via regioselective intermodular pauson-khand reactions
A new approach to the synthesis of prostaglandin and phytoprostanes B 1 is described. The key step is an intermolecular Pauson-Khand reaction between a silyl-protected propargyl acetylene and ethylene. This reaction, promoted by NMO in the presence of 4 A molecular sieves, afforded the 3-fert-butyldimethylsilyloxymethyl-2-substituted-cyclopent-2-en-1- ones (III) in good yield and with complete regioselectivity. Deprotection of the silyl ether, followed by Swern oxidation, gave 3-formyl-2-substituted- cyclopent-2-en-1-ones (II). Julia olefination of the aldehydes II with the suitable chiral sulfone enabled preparation of PPB1 type I and PGB1.
Vazquez-Romero, Ana,Cardenas, Lydia,Blasi, Emma,Verdaguer, Xavier,Riera, Antoni
supporting information; experimental part
p. 3104 - 3107
(2009/12/05)
A flexible synthesis of the phytoprostanes B1 type I and II
(Chemical Equation Presented) Syntheses of the enantiomerically pure phytoprostanes B1 type I and II are described starting from furfural and n-propylfuran. Key steps include the preparation of the Freimanis (±)-hydroxycyclopentenone and Wittig
El Fangour, Siham,Guy, Alexandre,Vidal, Jean-Pierre,Rossi, Jean-Claude,Durand, Thierry
p. 989 - 997
(2007/10/03)
Prostaglandin analogs and process of preparation thereof
Prostaglandin analogs and process for the preparation thereof as precursorsor the synthesis of oligomeric mixtures exhibiting biological activity for protection of oxidative phosphorylation of degraded mitochondria. The analogs have the general formula: STR1 synthesized by O-alkylating a 2-alkylcyclopentane-1,3-dione to form an enol ether, reacting the ether with CH2 =CHMgBr to form a vinyl, oxidizing the vinyl with OsO4 and NaIO4 to form an aldehyde, and reacting the aldehyde with a sodium salt of dimethyl (2-oxoalkyl)phosphonate.
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(2008/06/13)
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