19672-37-8Relevant academic research and scientific papers
Catalytic tandem C-C bond formation/cleavage of cyclopropene for allylzincation of aldehydes or aldimine using organozinc reagents
Nakano, Takeo,Endo, Kohei,Ukaji, Yutaka
supporting information, p. 1418 - 1421 (2014/04/03)
The tandem allylation of aldehydes or an aldimine with allylzinc intermediates derived from organozinc reagents and cyclopropenes is described. The present three-component reaction involves carbozincation of cyclopropene and sequential cleavage of a cyclopropylzinc intermediate in situ without a transition-metal catalyst. The allylzinc intermediates generated in situ, which is an α,β-unsaturated acylanion equivalent, gave the corresponding homoallylic alcohols or amine in good yields.
Yb(OTf)3-promoted effective benzylation and allylation with N-tosyl amino group as a stable leaving group
Liu, Jinqian,Wang, Limin,Zheng, Xingzhou,Wang, Aili,Zhu, Mengyun,Yu, Jianjun,Shen, Qiang
supporting information; experimental part, p. 1843 - 1846 (2012/04/23)
A simple, inexpensive, environmentally friendly, and highly efficient benzylation and allylation of 1,3-dicarbonyl compounds with sulfonamides in the presence of Yb(OTf)3 is described. Yb(OTf)3 was proved to be a good catalyst for the cleavage of sp3 carbon-nitrogen bond. Various 1,3-dicarbonyl compounds can couple with a broad range of tosyl-activated benzylic and allylic amines to give diversely functionalized products in good to excellent yields.
H5CoW12O40 supported on nano silica from rice husk ash: A green bifunctional catalyst for the reaction of alcohols with cyclic and acyclic 1,3-dicarbonyl compounds
Rafiee, Ezzat,Khodayari, Maryam,Kahrizi, Masoud,Tayebee, Reza
experimental part, p. 121 - 128 (2012/06/01)
Rice husk ash (RHA) is an abundant agricultural by-product. The present research work deals with the production of nano silica powders, with high surface area and in amorphous form, from RHA using optimized technique. 12-Tungestocobaltic acid, H5CoW12O40 (CoW), was supported on silica from RHA to produce silica supported CoW (CoW/NSiO 2) as a nano catalyst. The characterization data derived from FT-IR reveal that the Keggin structure of CoW remains intact in CoW/NSiO2. TEM image showed that the catalyst had spherical shape with an average particle size of 10 nm. The acidity of the catalyst was measured by potentiometric titration with n-butylamine. To our surprise, this very strong solid acid catalyst showed an excellent distribution of acid sites, suggesting that the catalyst possesses a higher number of surface active sites compared to CoW supported on commercial silica (CoW/SiO2), CoW and K 5CoW12O40. A high catalytic activity was found over CoW/NSiO2. Finally, CoW/NSiO2 has been used as a highly effective catalyst for benzylation of linear 1,3-dicarbonyl compounds with benzylic alcohols and synthesis of β-keto enol ethers from cyclic 1,3-dicarbonyl compounds. The present methodology offers a practical, simple, mild, environmentally friendly, and timesaving method under solvent-free conditions.
Direct benzylation and allylic alkylation in high-temperature water without added catalysts
Hirashita, Tsunehisa,Kuwahara, Sho,Okochi, Sota,Tsuji, Makoto,Araki, Shuki
scheme or table, p. 1847 - 1851 (2010/09/07)
In high-temperature water a series of benzyl and allylic alcohols reacted with 1,3-dicarbonyl compounds and activated aromatic compounds to give the alkylated products without added catalysts.
Fe(ClO4)3·×H2O-Catalyzed direct C-C bond forming reactions between secondary benzylic alcohols with different types of nucleophiles
Thirupathi, Ponnaboina,Kim, Sung Soo
experimental part, p. 2995 - 3003 (2010/06/14)
Fe(ClO4)3·×H2O as a highly effective catalyst for benzylation of 1,3-dikones, β-ketoesters, 1,3-diesters, electron-rich arenes and heteroarenes and 4-hydroxycoumarin with various benzylic alcohols is described. The usefulness of this procedure is shown by a synthesis of bis-symmetrical triarylmethanes and one step synthesis of an anti-coagulant compound 4-hydroxy-3-(1,2,3,4-tetrahydronaphthalen-1-yl)-2H-chromen-2-one (Coumatetralyl (B)). The advantages of this protocol are broad scope, mild conditions, use of inexpensive catalyst and simplicity of operation since water is the only side product.
Selective benzylic and allylic alkylation of protic nucleophiles with sulfonamides through double Lewis acid catalyzed cleavage of sp3 carbon-nitrogen bonds
Liu, Cong-Rong,Li, Man-Bo,Yang, Cui-Feng,Tian, Shi-Kai
experimental part, p. 793 - 797 (2009/09/29)
The acid-catalyzed benzylic and allylic alkylation of protic nucleophiles is fundamentally important for the formation of carbon-carbon and carbon-heteroatom bonds, and it is a formidable challenge for benzylic and allylic amine derivatives to be used as the alkylating agents. Herein we report a highly efficient benzylic and allylic alkylation of protic carbon and sulfur nucleophiles with sulfonamides through double Lewis acid catalyzed cleavage of sp3 carbon-nitrogen bonds at room temperature. In the presence of a catalytic amount of inexpensive ZnCl2-TMSCl (TMSCl: chlorotrimethylsilane), 1,3-diketones, β-keto esters, β-keto amides, malononitrile, aromatic compounds, thiols, and thioacetic acid can couple with a broad range of tosylactivated benzylic and allylic amines to give diversely functionalized products in good to excellent yields and with high regioselectivity. Furthermore, the cross-coupling reaction of 1,3-dicarbonyl compounds with benzylic propargylic amine derivatives has been successfully applied to the one-step synthesis of polysubstituted furans and benzofurans.
Direct carbon-carbon bond formation from alcohols and active methylenes, alkoxyketones, or indoles catalyzed by indium trichloride
Yasuda, Makoto,Somyo, Toshio,Baba, Akio
, p. 793 - 796 (2007/10/03)
(Chemical Equation Presented) The unsalted variety: The direct coupling reaction of alcohols with active methylenes, alkoxyketones, or indoles catalyzed by InCl3 proceeds without the formation of metal salts (see scheme). As H2O is the only by-product of this system, the alkylated products are easily isolated in pure form, and the reaction is suitable for large-scale synthesis.
TRIAZINE COMPOUNDS AND THEIR USE
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Page 25, (2010/02/09)
A compound of formula (I) wherein R1 is hydrogen, alkyl, -alkyl-aryl, -alkyl-heterocycloalkyl or -alkyl-0-heterocycloalkyl; R2 is hydrogen, hydroxy, amino, nitro, alkoxy, alkyl, aryl or heteroaryl; R3 is hydrogen, alkyl or
Cobalt-mediated alkylation of β-dicarbonyl compounds. Electrochemical evidence of cobalt(l) intermediate species and HPLC-MS detection of reaction intermediates
Anhari,Gallardo,Vallribera
, p. 93 - 97 (2007/10/03)
The alkylation reactions of Co(II) acetylacetonate with alkyl halides are triggered by electrochemical reduction of the complex. This confirms Co(I) species as intermediates. HPLC-MS analysis of the reaction mixtures has permitted identification of some cobalt-containing intermediates involved in the alkylation reactions. Based on these results we propose a mechanistic hypothesis for the formation of dialkylation products and Co(III) acetylacetonate. Springer-Verlag Iberica 1997.
Substituent Effects on the CC Bond Strength, 16. - Thermal Stability and Enthalpies of Formation of β-Dicarbonyl Compounds. - Stabilisation Enthalpies of α,α'-Diketoalkyl Radicals
Noelke, Margot,Verevkin, Sergej P.,Beckhaus, Hans-Dieter,Ruechardt, Christoph
, p. 41 - 52 (2007/10/02)
The geminal interactions of the two carbonyl groups in seven β-diketones of the type 8-9 and 11-13 were estimated from their enthalpies of formation, which were deduced from their heats of combustion and enthalpies of vaporization.The radical stabilisation enthalpies RSE of the α,α'-diketoalkyl radicals 9-13 were obtained from the enthalpies of activation ΔH(excit.) of thermal CC bond cleavage of eight model compounds of the type 9-13 by their comparison with ΔH(excit.) of comparable hydrocarbons of similar strain.For non-cyclic α,α'-diacylalkyl radicals and six-membered cyclic ones RSE = 54.8 +/- 1.3 kJ mol-1 was determined, which indicates an additive stabilisation by two carbonyl groups. - Key Words: Enthalpies of formation/ Geminal substituents, energetic interaction of/ Bond cleavage, C-C, kinetics of/ Radicals, stability of/ Increments, thermochemical/ Bond strength, substituent effects on
