- A mild method for the replacement of a hydroxyl group by halogen: 3. the dichotomous behavior of α-haloenamines towards allylic and propargylic alcohols
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A study of the deoxyhalogenation of allylic and propargylic alcohols with tetramethyl-α-halo-enamines is reported. Primary allylic and primary and secondary propargylic alcohols gave the corresponding halides in high yields. Secondary allylic and propargylic alcohols yielded the corresponding secondary halides but the reaction also produced some rearranged primary halides (I > Br > Cl). The reactions with tertiary allylic and tertiary propargylic alcohols gave several products and was therefore of little synthetic value. However, the addition of triethylamine to the reaction mixture or the use of lithium alkoxide instead of alcohol brought about a major change of the course of the reaction which led to amides carrying an allyl or an allenyl group at C2. This was shown to result from a Claisen-Eschenmoser rearrangement of an intermediate α-allyloxy- or propargyloxy-enamine.
- Munyemana, Fran?ois,Patiny, Luc,Ghosez, Léon
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- α-Selective Allylation of Isatin Imines Using Metallic Barium
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The Barbier-type allylation of isatin imines with allylic chlorides was achieved by using metallic barium as the promoter. Various α-allylated 3-amino-2-oxindoles were synthesized from the corresponding allylic chlorides and isatin imines. The double-bond geometry of allylic chlorides was retained throughout the reaction. An arylic bromide or iodide functionality of the products was robust to metalation under the optimum reaction conditions.
- Yanagisawa, Akira,Yamafuji, Seiya,Sawae, Toshiki
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supporting information
p. 2019 - 2023
(2016/08/09)
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- Reactivity of bismuth(III) halides towards alcohols. A tentative to mechanistic investigation
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The reactivity of bismuth(III) halides (BiX3; X=Cl, Br and I) towards a series of alcohols has been investigated. Three different reactions have been studied, namely: halogenation, dehydration and etherification. The behaviour of these bismuth derivatives was found to depend on the nature of the halide bonded to the bismuth atom. Their reactivities can be interpreted on the basis of the Hard and Soft Acids and Bases (HSAB) principle. A mechanism is proposed which involves the formation of a complex of the alcohol with Bi(III).
- Keramane, El Mehdi,Boyer, Bernard,Roque, Jean-Pierre
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p. 1909 - 1916
(2007/10/03)
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- Regio- and Stereoselective Substitution of Hydroxy Group in Allyl Alcohols by Halogen
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A preparative method for regio- and stereoselective substitution of the hydroxy group by halogen in allyl alcohols under the action of triphenylphosphine complexes with ethyl trichloroacetate or trichloroacetonitrile has been developed.The regio- and stereoselectivity of substitution of hydroxy group by halogen with triphenylphosphine complexes and compounds containing trichloromethyl group is compared.
- Matveeva, E. D.,Erin, A. S.,Mitroshin, D. B.,Kurts, A. L.
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p. 1019 - 1022
(2007/10/03)
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- Surface Catalyzed Hydrochlorination of 1,3-Butadiene
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The rates of disappearance of gaseous hydrogen chloride (-d/dt) and 1,3-butadiene and appearance of the gaseous products 3-chloro-1-butene and (E)- and (Z)-1-chloro-2-butene (+d/dt) in Pyrex IR cells at 295 K and total initial pressures of about 450 torr are found to be proportional to the surface-to-volume ratio (S/V) of the reaction vessel.
- Mascavage, Linda M.,Dalton, David R.
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p. 3461 - 3464
(2007/10/02)
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- Surface-Catalyzed Hydrochlorination of Alkenes. The Reaction of the Gases Hydrogen Chloride and 1,3-Butadiene
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Mixtures of gaseous hydrogen chloride and gaseous 1,3-butadiene at total pressures less than 1 atm and at temperatures between 294 and 334 K yield mixtures of 3-chloro-1-butene and (E)- and (Z)-1-chloro-2-butene.The ratio of the product of putative 1,2-addition to those of 1,4-addition is approximately unity with only the amount of (Z)-1-chloro-2-butene increasing from ca. 2percent of the total reaction product mixture at the lower temperature to ca. 4percent at the higher temperature.Kinetic measurements have been made by observing the reaction throughout its course utilizing FT-IR spectroscopy.It is concluded that surface catalysis is required for product formation and that the reaction, which occurs at the walls, is most probably between multilayer adsorbed hydrogen chloride and gaseous or weakly adsorbed 1,3-butadiene.
- Mascavage, Linda M.,Chi, Hongji,La, Sangmoo,Dalton, David R.
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p. 595 - 601
(2007/10/02)
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- SYNTHESIS OF ALKYL HALIDES UNDER NEUTRAL CONDITIONS
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Primary and secondary alcohols are efficiently converted to the corresponding alkyl halides under neutral conditions.
- Munyemana, Francois,Frisque-Hesbain, Anne-Marie,Devos, Alain,Ghosez, Leon
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p. 3077 - 3080
(2007/10/02)
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- STEREOHOMOGENEUS SYNTHESIS OF (E)- AND (Z)-CROTYLTRIFLUOROSILANES AND HIGHLY STEREOSELECTIVE ALLYLATION OF ALDEHYDES
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Stereohomogeneus (E)- and (Z)-crotyltrifluorosilanes were prepared and used for the highly diastereoselective synthesis of threo- and erythro-β-methylhomoallyl alcohols, respectively, from aldehydes in the presence of fluoride ions.The mechanism of the reaction was discussed.
- Kira, Mitsuo,Hino, Takakazu,Sakurai, Hideki
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p. 1099 - 1102
(2007/10/02)
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- Process for preparation of carboxylic acid ester containing fluorine
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Process for the preparation of carboxylic acid ester containing fluorine comprises the reaction of the reaction mixture obtained by the reaction of an organic halogen compound containing fluorine expressed by a general formula, , X - Rf- X′, , (in which, X and X′ independently stand for halogen atoms and Rfis an optionally fluorinated hydrocarbon) with carbon dioxide in the presence of zinc, with a halogenated hydrocarbon expressed by a general formula,, RY, , (in which R is an optionally fluorinated hydrocarbon and Y is a chlorine, bromine or iodine atom).
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- HOMOLYTIC DISPLACEMENT AT CARBON CENTRES. XII. REGIOSPECIFIC FORMATION OF N-ALLYL AND N-CYCLOPROPYLCARBINYL SULPHONAMIDES AND OF ALLYL AND CYCLOPROPYL HALIDES IN THE REACTION OF N-HALOGENO COMPOUNDS WITH ORGANOCOBALOXIMES
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Several but-3-enyl and allylcobaloximes react regiospecifically with N-chloro-N-methyl sulphonamides to give N-cyclopropylcarbinyl- or rearranged N-allyl-N-methyl sulphonamides, by a process which is believed to take place by the attack of an N-centred radical at the terminal unsaturated carbon of the organic ligand, with displacement of cobaloxime(II).In contrast, N-bromoacetamide and several other N-halogenoimides react regiospecifically to the cyclopropylcarbinyl halide or the rearranged allyl halide by a process in which a halogen-containing free radical species attacks the terminal unsaturated carbon of the organocobaloxime.
- Johnson, Michael D.,Lampman, Gary M.,Koops, Roger W.,Gupta, B. Das
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p. 281 - 288
(2007/10/02)
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- Process for production of 2,6-di-tert-alkenyl phenols
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There is disclosed a process for the production of 2,6-di-tert-alkyl-4-alkenyl phenols wherein the improvement comprises the reaction of a 2,6-di-tert-alkyl phenol with an allyl halide to yield the 2,6-di-tert-alkyl-4-alkenyl phenol through the use of a triphase or polymer bound catalyst.
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