4031-37-2Relevant articles and documents
Synthesis and chemistry of 2,3-dioxabicyclo[2.2.2]octane-5,6-diols
Valente, Peter,Avery, Thomas D.,Taylor, Dennis K.,Tiekink, Edward R. T.
supporting information; experimental part, p. 274 - 282 (2009/04/10)
(Chemical Equation Presented) 1,4-Disubstituted 2,3-dioxabicyclo[2.2.2]oct- 5-enes were dihydroxylated with osmium tetroxide to yield diols anti to the peroxide linkage in a highly selective manner. Reduction of the peroxide bond furnished cyclohexane-1,2,3,4-tetraols with toxocarol relative stereochemistry in excellent yield. This new methodology was employed to synthesize the natural product (1S,2R,3S,4R,5R)-2-methyl-5-(propan-2-yl)cyclohexane-1,2,3,4-tetrol (1) in a short sequence from (R)-α-phellandrene. Moreover, during the study of the chemistry of 2,3-dioxabicyclo[2.2.2]octane-5,6-diols a hitherto unknown rearrangement was discovered which has wide applicability for the synthesis of 1,4-dicarbonyls, including optically enriched synthons. A broad range of mechanistic investigations applicable to this rearrangement are also reported.
Ruthenium(II)-Catalyzed Reactions of 1,4-Epiperoxides
Suzuki, Masaaki,Ohtake, Hiroaki,Kameya, Yoshimi,Hamanaka, Nobuyuki,Noyori, Ryoji
, p. 5292 - 5302 (2007/10/02)
The behavior of 1,4-epiperoxides in the presence of transition-metal complexes is highly dependent on the structures of the substrates and the nature of the metal catalysts.Reaction of saturated epiperoxides such as 1,3-epiperoxycyclopentane, 1,4-epiperoxycyclohexane, or dihydroascaridole catalyzed by RuCl2(PPh3)3 in dichloromethane gives a mixture of products arising from fragmentation, rearrangement, reduction, disproportionation, etc.Prostaglandin H2 methyl ester undergoes clean and stereospecific fragmentation to afford methyl(5Z,8E,10E,12S)-12-hydroxy-5,8,10-heptadecatrienoate and malonaldehyde.Bicyclic 2,3-didehydro 1,4-epiperoxides give the syn-1,2:3,4-diepoxides by the same catalyst.The monocyclic analogues are transformed to a mixture of diepoxides and furan products.The stereochemical outcome of the epoxide formation reflects unique differences in the ground-state geometry of the starting epiperoxide substrates.FeCl2(PPh3)2 serves as a useful catalyst for the skeletal change of sterically hindered bicyclic 2,3-didehydro 1,4-epiperoxides to the syn-diepoxides.In addition, the Fe complex best effects the conversion of 1,4-unsubstituted 2,3-didehydro epiperoxides to furans.The Ru-catalyzed reactions are interpreted in terms of the intermediacy of inner-sphere radicals formed by atom transfer of the Ru(II) species to peroxy substrates, in contrast to the Fe-catalyzed reactions proceeding via free, outer-sphere radicals generated by an electron-transfer mechanism.
On agents favoring prostaglandin F formation during biosynthesis
Chan,Nagasawa,Takeguchi,Sih
, p. 2987 - 2991 (2007/10/14)
The microsomal fraction of bovine vascular gland catalyzed the conversion of eicosapolyenoic acids exclusively to prostaglandin E in the presence of reduced glutathione, while hydroxy fatty acids, prostaglandins D and F, decreased to a negligible level. After solubilizing the microsomal fraction with cutscum, the prostaglandin synthetase activity was purified 11 fold by batchwise absorption and elution of the enzyme activity from DEAE cellulose. This partially purified enzyme fraction did not respond to reduced glutathione in promoting prostaglandin E formation at the expense of other products. A number of glutathione analogs were examined, but none of these was as effective as reduced glutathione. Dithiol complexes of Cu2+, Ni2+, and Zn2+ exerted pronounced effects on relative amounts of the different prostaglandins biosynthesized. Both the Cu2+ dithiothreitol (2:1) complex and stannous chloride markedly enhanced prostaglandin F synthesis at the expense of prostaglandin D and prostaglandin E. The following reagents chemically reduced the endoperoxide in ascaridole to p menth 2 ene cis 1,4 diol: Cu2+ dithiothreitol, Cu2+ epinephrine, and stannous chloride. It is concluded that the enhancement of prostaglandin F formation caused by copper dithiols and L epinephrine is due to nonenzymatic reduction of prostaglandin G or prostaglandin H.
