279-35-6Relevant articles and documents
Face Selectivity in the Reduction with Dideuteriodi-imide of Endoperoxides derived from the Singlet Oxygenation of Cycloalka-1,3-dienes
Bloodworth, A. J.,Eggelte, Henny J.
, p. 2069 - 2072 (1984)
Four dioxabicycloalkenes (n = 1-4) have been reduced with dideuteriodi-imide.For each reduction, the ratio of the amount of product arising from cis-addition of two deuterium atoms to the face of the double bond syn to the dioxygen bridge to that arising from addition to the anti face has been determined by 1H-decoupled 2H n.m.r. spectroscopy, and the structures of the individual isomers have been determined by 1H n.m.r. spectroscopy.The cyclopentadiene endoperoxide (n = 1) yields exclusively the anti-isomer, whereas the cyclohexadiene endoperoxide (n = 2) affords a mixture containing 66percent of syn isomer, and the cycloheptadiene and cyclo-octadiene endoperoxides (n = 3 and 4) give only the syn isomer.The results are consistent with the expected variation across the series in both electronic and steric effects.
Triphenylphosphine reduction of saturated endoperoxides
Erden, Ihsan,Gaertner, Christian,Saeed Azimi
supporting information; experimental part, p. 3986 - 3989 (2009/12/05)
(Figure Presented) Triphenylphosphine reduction of saturated endoperoxides derived from 6,6-dimethylfulvene and spiro[2.4]hepta-4,6-diene in the presence of nucleophiles results in the formation of products that mainly stem from deoxygenation followed by carbocation formation. Nucleophilic attack by solvent proceeds by an SN1 like mechanism; allyl shifts and cyclopropylcarbinyl-cyclobutyl rearrangements also occur. With the systems lacking carbocation-stabilizing groups, the deoxygenation step is preceded by attack of H2O at the phosphorus.
Extreme rate acceleration by axial thiolate coordination on the isomerization of endoperoxide catalyzed by iron porphyrin
Yamane, Takehiro,Makino, Kohei,Umezawa, Naoki,Kato, Nobuki,Higuchi, Tsunehiko
supporting information; experimental part, p. 6438 - 6440 (2009/03/11)
(Chemical Equation Presented) A coordinated effort: The isomerization mechanism of prostaglandin H2 (PGH2), which is catalytically isomerized to prostacyclin or thromboxane A2 by cytochrome P450s, was investigated using a hemethiolate complex and an endoperoxide. Isomerization of endoperoxides proceeded very rapidly with this complex, whereas imidazole- or chloride-ligated heme had slight or no catalytic activity (see scheme).
Time-resolved infrared studies of triplet 1,3-cyclopentanediyl
Showalter, Brett M.,Bentz, Timothy C.,Ryzhkov, Lev R.,Hadad, Christopher M.,Toscano, John P.
, p. 309 - 312 (2007/10/03)
Triplet-sensitized photolysis of 2,3-diazabicyclo[2.2.1]hept-2-ene (1) in argon- or oxygen- saturated acetonitrile-d3 solutions results in the formation of bicyclo[2.1.0]pentane (3), a ring closure product arising from an intermediate 1,3-cyclopentanediyl triplet biradical (2). Time-resolved infrared (TRIR) spectroscopy was used to monitor the kinetics of bicyclopentane 3 production. This analysis provides a measurement of the triplet biradical lifetime and an estimate of the bimolecular reaction rate between biradical 2 and oxygen, both in good agreement with previous investigations. Our studies also indicate that certain IR bands due to 3 in the C-H stretching region overlap with corresponding bands in biradical 2. This interpretation is supported by computational investigations. Copyright
Oxymetallation. Part 23. Peroxymercuriation of Bicycloalkanes
Bloodworth, A. J.,Chan, Kam Hung,Cooksey, Christopher J.,Hargreaves, Neville
, p. 1923 - 1930 (2007/10/02)
The peroxymercuriations of bicycloalkanes, n = 2-4, have been carried out using mercury(II)acetate and a one-fold excess of t-butyl hydroperoxide in dichloromethane with 20 molpercent of perchloric acid as catalyst, the products being isolated, after anion exchange, as the organomercury(II)bromides.Small amounts of acetoxymercurials are also formed but are easily removed by silica chromatography.Bicyclopentane reacts by exclusive cleavage of the zero-bridge to give cis-1-bromo-mercurio-3-t-butylperoxycyclopentane 4, but competing isomerisation to cyclopentene consumes ca. 50percent of the cyclopropane.Reaction in neat t-butyl hydroperoxide without perchloric acid gives only the peroxymercurial 4.This has been converted into 2,3-dioxabicycloheptane 2a by iododemercuriation then reaction with silver trifluoroacetate.Bicycloheptane reacts by exclusive cleavage of the one-bridge to give cis- and trans-1-bromomercuriomethyl-2-t-butylperoxycyclohexanes 28 and 29, which have been reduced with alkaline sodium borohydride to afford the corresponding 1-methyl compounds 32 and 33.Bicyclohexane reacts by both zero-bridge and one-bridge cleavage to give the γ-peroxymercurials trans-1-bromomercuriomethyl-2-t-butylperoxycyclopentane 10 and 1-bromomercurio-3-t-butylperoxycyclohexane 13.Also formed is a similar amount of the isomeric β-peroxymercurials 1-bromomercuriomethyl-1-t-butylperoxycyclopentane 11 and trans-1-bromomercurio-2-t-butylperoxycyclohexane 14 yet neither starting cyclopropane nor product γ-peroxymercurial is isomerised by perchloric acid.These unusual rearrangements are also obtained with n-butyl hydroperoxide but not with methanol, butanol or acetic acid as nucleophile.They do not take place with other strong acid catalysts, and are inhibited by 2,6-di-t-butyl-4-methylphenol and promoted by di-t-butyl peroxyoxalate.Reaction in neat t-butyl hydroperoxide at 60 deg C without perchloric acid gives only the γ-peroxymercurials 10 and cis-13.Iododemercuriation of the cis-1,3-cyclohexane derivative cis-13. then reaction with silver trifluoroacetate, gives mainly 3-t-butoxycyclohexanone 27 rather than 6,7-dioxabicyclooctane.
CONVERSION OF BICYCLOPENTANE INTO 2,3-DIOXABICYCLOHEPTANE VIA t-BUTYL PEROXYMERCURIATION
Bloodworth, A. J.,Hargreaves, Neville
, p. 2783 - 2784 (2007/10/02)
Bicyclopentane has been converted in 45 percent yield into 2,3-dioxabicycloheptane by the sequence t-butyl peroxymercuriation, iodomercuriation, epimerisation of the resultant 1-t-butylperoxy-3-iodocyclopentane, and reaction of the trans isomer with silver trifluoroacetate.
UV Laser Photochemistry: Triplet Biradical Trapping Efficiencies and Lifetimes
Adam, Waldemar,Hannemann, Klaus,Wilson, R. Marshall
, p. 929 - 935 (2007/10/02)
The trapping of triplet 1,3-cyclopentadiyl (1a) and the triplet 1,4-biradical 2-cyclopent-2-enyl (6) with molecular oxygen has been studied quantitatively.The lifetime of 1a has been found to range between 720 and 900 ns and that of 6 between 53 and 94 ns depending on the solvent.The biradical 1a was found to be trapped in essentially quantitative yield with no indication of oxygen-catalyzed intersystem crossing.In contrast, 6 was found to be trapped in 54-79percent yield with the residual biradical quenching being due to oxygen-catalyzed intersystem crossing.These and other biradical trapping data have been correlated with 1,3-biradical geometries and found to be in accord with Salem's rules for spin-orbit coupling in triplet biradicals.
