- Applications of allylsamarium bromide as a grignard reagent and a singleelectron transfer reagent in the one-pot synthesis of dienes and trienes
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The utility of allylsamarium bromide, both as a nucleophilic reagent and a single-electron transfer (SET) reagent in the reaction of α-halo, γ-halo-αβ-unsaturated ketones and esters with allylsamarium bromide is reported for the first time in this paper. From a synthetic point of view, a general, efficient and experimentally simple one-pot method for the preparation of 1,4-dienes and trienes is developed. A possible mechanism of the transformation is proposed.
- Hu, Yuanyuan,Zhao, Tao,Zhang, Songlin
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supporting information; experimental part
p. 1697 - 1705
(2010/06/17)
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- Remarkable enhancement of Lewis acidity of chlorosilane by the combined use of indium(III) chloride
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A combination of InCl3 and R3SiCl provided a strong Lewis acid catalyst for such reactions as allylation, hydrosilation and Friedel-Crafts alkylation. Especially, catalytic Sakurai-Hosomi-type allylation was accomplished with high yield and selectivity. The silicon atom is assumed to be the acidic center of the combined system, and the catalytic activity largely depends on the substituents on the silicon center.
- Onishi, Yoshiyuki,Ito, Takeshi,Yasuda, Makoto,Baba, Akio
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p. 8227 - 8235
(2007/10/03)
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Reaction of alkyl hydroperoxides (1(ary), 2(ary) or 3(ary)) upon tertiary alkyl trichloroacetimidates under acidic catalysis yielded unsymmetrical dialkyl peroxides with yields in the range 30-70%.
- Bourgeois,Montaudon,Maillard
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p. 2477 - 2484
(2007/10/02)
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- A Versatile Synthesis of 1,4-Dienes: Use of Vinyl Ethers as Vinyl Cation Equivalents
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The α,β-dibromo ethers 2, in situ generated from the vinyl ethers 1 and bromine, react with the allylsilanes 3 in the presence of ZnCl2 to give the β-bromo ethers 4.Treatment of 4 with Na in diethyl ether yields 1,4-dienes 5 in 62-79percent overall yield.Key Words: Enol ether / Allylsilane / Bromo ether / 1,4-Diene / Alkoxyalkylation
- Ohm, Stefan,Baeuml, Englbert,Mayr, Herbert
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p. 2785 - 2790
(2007/10/02)
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- Reactivity of hypervalent species of silicon: cleavage of the allyl-silicon bond
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The reactivities of the silicon-allyl bonds in two kinds of pentacoordinated silicon species CH2=CHCH2Si(o-O2C6H4)2-NMe4+ (1) and CH2=CHCH2Si(OCH2CH2)3N (2) has been compared.In the allyl transfer to carbonyl compounds under nucleophilic conditions (NaOMe, KF or Bu4NF) and electrophilic conditions (TiCl4, AlCl3, BF3) these two species show quite different behaviour.Complex 1 is activated by nucleophiles, while for 2 transfer occurs under electrophilic conditions.These results indicate that the reactivity of these species is a function of their overall charge and geometry.
- Cerveau, Genevieve,Chuit, Claude,Corriu, Robert J. P.,Reye, Catherine
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p. C17 - C20
(2007/10/02)
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- FORMATION OF SULPHUR COMPOUNDS IN HYDRODENITROGENATION OF QUINOLINE, 1,2,3,4-TETRAHYDROQUINOLINE, PYRIDINE, PIPERIDINE AND 1-PENT-4-ENYLAMINE ON A NICKEL-TUNGSTEN CATALYST IN THE PRESENCE OF HYDROGEN SULPHIDE
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Hydrodenitrogenation (HDN) of quinoline and 1,2,3,4-tetrahydroquinoline on a sulphided nickel-tungsten catalyst in the presence of hydrogen and of its mixture with hydrogen sulphide has been studied in an autoclave at 350 deg C.The results show that hydrogen sulphide exhibits rate-accelerating effect on HDN of the above compounds by formation of sulphur compounds.It was found that neutral portion of the reaction mixture contains octahydro-2H-1-benzothiopyran, octahydro-1H-2-benzothiopyran, octahydro-2-methylbenzo(b)thiophene and other sulphur compounds.The reaction scheme for HDN of quinoline that accounts for favourable effect of hydrogen sulphide is proposed.In the neutral portion of the reaction mixture from HDN of piperidine and 1-pent-4-enylamine in the presence of hydrogen sulphide further sulphur-containing compounds were identified.
- Cerny, Mirko,Trka, Antonin
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p. 1749 - 1758
(2007/10/02)
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- The 9-Decalyl and Related Cations. VI Solvolysis of Pent-4-enyl p-Nitrobenzenesulfonate in 1,1,1,3,3,3-Hexafluoropropan-2-ol and of 3-(Cyclohex-1'-enyl)propyl p-Nitrobenzenosulfonate in 2,2,2-Trifluoroethanol and 1,1,1,3,3,3-Hexafluoropropan-2-ol
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Kinetic and product studies have established that pent-4-enyl p-nitrobenzenesulfonate undergoes insignificant solvolysis (1.5percent) by the ?-route in 1,1,1,3,3,3-hexafluoropropan-2-ol. ?-Participation to give the perhydroinden-3a-yl (8-hydrindyl)cation during the solvolysis of 3-(cyclohex-1'-enyl)propyl p-nitrobenzenesulfonate, a substituted pent-4-enyl derivative, in fluorinated alcohols is, however, significant.In buffered 2,2,2-trifluoroethanol, it occurs to the extent of 30percent; in buffered and unbuffered 1,1,1,3,3,3-hexafluoropropan-2-ol, the values are 96 and 98percent, respectively.
- Ferber, Peter H.,Gream, George E.
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p. 1051 - 1061
(2007/10/02)
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- Synthesis of Olefins from α-Chlorocarbonyl Compounds
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Olefins or diolefins with the double bonds in predetermined positions are obtained in moderate to good yields by treatment of α-chlorocarbonyl compounds with Grignard reagents and lithium in a single process.
- Barluenga, Jose,Yus, Miguel,Concellon, Jose M.,Bernad, Pablo
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p. 677 - 692
(2007/10/02)
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