- Revisiting the Corey-Chaykovsky reaction: The solvent effect and the formation of β-hydroxy methylthioethers
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The classical Corey-Chaykovsky (CC) reaction of ketones in ethereal solvents (i.e., THF or Et2O) resulted in the production of a significant amount of β-hydroxy methylthioether 2 along with normal epoxide product 1. Some interesting and synthet
- Peng, Yu,Yang, Jin-Hui,Li, Wei-Dong Z.
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p. 1209 - 1215
(2007/10/03)
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- OXYDATION D'ALCENES CYCLIQUES PAR L'IODYLBENZENE CATALYSEE PAR L'ACETYLACETONATE DE VANADYLE
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Iodylbenzene with vanadyl acetylacetonate oxidizes cyclic alkenes, the experimental results accord with a free radical oxidation mechanism.
- Barret, R.,Pautet, F.,Daudon, M.,Mathian, B.
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p. 439 - 440
(2007/10/02)
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- Reaction of Lithium with Alkylidene Halides and Carbonyl Compounds
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While benzylidene bromide reacts with aromatic aldehydes and lithium to give stilbenes, the reaction with aliphatic carbonyl compounds as well as that of alkylidene halides with carbonyl compounds and lithium are complicated by several competing side reactions.
- Pasha, M. A.,Ravindranath, B.
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p. 781 - 782
(2007/10/02)
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- Hydroxylation by Cytochrome P-450 and Metalloporphyrin Models. Evidence for Allylic Rearrangement
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The allylic hydroxylation of 3,3,6,6-tetradeuteriocyclohexene, methylenecyclohexane, and β-pinene has been examined with phenobarbital-induced liver microsomal cytochrome P-450 (P-450LM2) and with iron porphyrin and chromium porphyrin model systems.Aerobic and peroxide dependent enzymic regimes were investigated with purified P-450LM2 and with microsomal suspensions.Epoxidation and allylic hydroxylation were primary reactions with all substrates.With 3,3,6,6-tetradeuteriocyclohexene, the major hydroxylation product (60-80percent) was the result of hydroxylation at the deuterated allylic site.In all cases, a significant amount (20-40percent) of hydroxylation occurred with allylic rearrangement.The iron porphyrin/iodosylbenzene model system also showed preferential hydroxylation of the deuterated allylic site (70percent) with significant allylic rearrangement (30percent).By contrast, the chromium porphyrin/iodosylbenzene model system showed complete scrambling of the allylic system.Extensive rearrangement accompanied the hydroxylation of methylenecyclohexane and β-pinene by both the enzymic and metalloporphyrin systems whereas the selenium dioxide oxidation of these substrates gave selective allylic hydroxylation without rearrangement.A mechanism is suggested for allylic hydroxylation by cytochrome P-450 and by the metalloporhyrin model systems involving initial hydrogen atom abstraction from the allylic site and geminate, cage recombination of the incipient, allylic free radical.
- Groves, John T.,Subramanian, Durga V.
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p. 2177 - 2181
(2007/10/02)
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- Preparative Oxidation of Cycloalkanes with O(3P) Atoms. Microwave Discharge of CO2 as a Source of O(3P) Atoms.
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Reaction of O atoms produced by CO2 discharge with cycloalkanes leads to their hydroxy, keto, and epoxy derivatives.The main products of oxidation of isomeric 1,2-dimethylcyclohexanes and cis-decalin were their respective tertiary alcohols formed with a high retention of configuration.This oxidation proceeds via radical mechanism, and the alcohols are formed by radical combination in a solvent cage.The influence of temperature and of O2 on the relative product distribution was investigated.
- Zadok, Elazar,Mazur, Yehuda
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p. 2223 - 2225
(2007/10/02)
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- Studies on the Autoxidation of Some Monocyclic Olefins
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The autoxidations of cyclopentene, cyclohexene, cycloheptene, cyclooctene, cycloocta-1,5-diene, 1-methylcyclopentene, 1-methylcyclohexene, 1-methylcycloheptene, 1-methylcyclooctene, methylene cyclopentene, and methylene cyclohexene with pure oxygen under normal pressure were studied.The epoxides formed were determined gaschromatographically.In most cases also the products of allylic oxidation were analyzed and their structures elucidated after reduction to the corresponding allyl alcohols.The portions of high boiling or polymeric products which could not be detected gaschromatographically and also the real yields of epoxides were determined by balance experiments in the presence of inert internal standards.
- Blau, K.,Mueller, U.,Pritzkow, W.,Schmidt-Renner, W.,Sedshaw, Z.
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p. 915 - 932
(2007/10/02)
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