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Igor B. Sivaev - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Functional Derivatives of 7,8-Dicarba-nido-undecaborate Anion by Ring-Opening of Its Cyclic Oxonium Derivatives
Collection of Czechoslovak Chemical Communications, 2020Co-Authors: Marina Yu. Stogniy, Ekaterina N. Abramova, Irina A. Lobanova, Igor B. Sivaev, Vikentii I. Bragin, Pavel V. Petrovskii, Viktoria N. Tsupreva, Olga V. Sorokina, Vladimir I. BregadzeAbstract:A new approach to synthesis of functional derivatives of 7,8-dicarba- nido -undecaborate anion based on ring-opening of its cyclic Oxonium derivatives [10-(CH 2 ) 4 O-7,8-C 2 B 9 H 11 ] and [10-O(CH 2 CH 2 ) 2 O-7,8-C 2 B 9 H 11 ] with various nucleophiles was developed. Both cyclic Oxonium derivatives can be obtained as single isomers by reaction of the parent anion [7,8-C 2 B 9 H 12 ] - with mercury(II) chloride in the corresponding solvents. Mechanism of formation of the cyclic Oxonium derivatives of 7,8-dicarba- nido -undecaborate anion was proposed. A series of 7,8-dicarba- nido -undecaborate derivatives with terminal carboxylic and azide functions were prepared by the ring-opening reactions of the cyclic Oxonium derivatives with substituted phenolate and azide ions, respectively.
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synthesis of Oxonium derivatives of the dodecahydro closo dodecaborate anion b12h12 2 tetramethylene Oxonium derivative of b12h12 2 as a convenient precursor for the synthesis of functional compounds for boron neutron capture therapy
Polyhedron, 2000Co-Authors: Igor B. Sivaev, Andrei A Semioshkin, Bernd Brellochs, Stefan Sjoberg, V I BregadzeAbstract:Direct synthesis of Oxonium derivatives of the dodecahydro-closo-dodecaborate anion is described and the reaction mechanism is discussed. Various derivatives of the [B12H12](2-) anion containing hydroxyl, amine, acid, and amino acid functions were prepare
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Synthesis of Oxonium derivatives of the dodecahydro-closo-dodecaborate anion [B12H12]2−. Tetramethylene Oxonium derivative of [B12H12]2− as a convenient precursor for the synthesis of functional compounds for boron neutron capture therapy
Polyhedron, 2000Co-Authors: Igor B. Sivaev, Andrei A Semioshkin, Bernd Brellochs, Stefan Sjoberg, Vladimir I. BregadzeAbstract:Direct synthesis of Oxonium derivatives of the dodecahydro-closo-dodecaborate anion is described and the reaction mechanism is discussed. Various derivatives of the [B12H12](2-) anion containing hydroxyl, amine, acid, and amino acid functions were prepare
Anil K Saikia - One of the best experts on this subject based on the ideXlab platform.
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diastereoselective synthesis of substituted dihydropyrans via an Oxonium ene cyclization reaction
Organic and Biomolecular Chemistry, 2012Co-Authors: Pipas Saha, Priya Ghosh, Sabera Sultana, Anil K SaikiaAbstract:Substituted dihydropyrans can be efficiently synthesized in good yields with excellent diastereoselectivity from the reaction of aldehydes or epoxides and ethyl 3-alkyl-3-hydroxy-5-methylhex-5-enoate via an Oxonium–ene cyclization reaction catalyzed by trimethylsilyl trifluoromethanesulfonate (TMSOTf) under mild conditions.
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Diastereoselective synthesis of substituted dihydropyrans via an Oxonium–ene cyclization reaction
Organic and Biomolecular Chemistry, 2012Co-Authors: Pipas Saha, Priya Ghosh, Sabera Sultana, Anil K SaikiaAbstract:Substituted dihydropyrans can be efficiently synthesized in good yields with excellent diastereoselectivity from the reaction of aldehydes or epoxides and ethyl 3-alkyl-3-hydroxy-5-methylhex-5-enoate via an Oxonium–ene cyclization reaction catalyzed by trimethylsilyl trifluoromethanesulfonate (TMSOTf) under mild conditions.
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synthesis of 2 3 5 6 tetrasubstituted tetrahydropyrans via 3 5 Oxonium ene reaction
Organic and Biomolecular Chemistry, 2012Co-Authors: Pipas Saha, Anup Bhunia, Anil K SaikiaAbstract:An efficient method for the synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans has been developed from the reaction of aldehydes and ethyl 2-(1-hydroxyalkyl/hydroxy(phenyl)methyl)-5-methylhex-4-enoate using (3,5)-Oxonium-ene reaction promoted by boron trifluoride etherate in good yields under mild conditions.
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stereoselective synthesis of 6 oxabicyclo 3 2 1 octene via 3 5 Oxonium ene reaction
Tetrahedron, 2012Co-Authors: Pipas Saha, Anil K SaikiaAbstract:Abstract Oxabicyclo[3.2.1]octene can efficiently be synthesized by the reaction of (−)-terpinen-4-ol and aldehyde or epoxide catalyzed by indium triflate (In(OTf)3) in good yields. The reaction is stereoselective and proceeds via (3,5)-Oxonium-ene-type reaction.
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a novel synthesis of oxabicyclo 3 3 1 nonanone via 3 5 Oxonium ene reaction
Organic Letters, 2010Co-Authors: Pipas Saha, U C Reddy, Somasekhar Bondalapati, Anil K SaikiaAbstract:Oxabicyclo[3.3.1]nonanone can conveniently be prepared by the reaction of trans-p-menth-6-ene-2,8-diol and aldehyde or epoxide mediated by boron trifluoride etherate in good yields. The reaction proceeds via (3,5)-Oxonium−ene-type reaction.
Wenhao Hu - One of the best experts on this subject based on the ideXlab platform.
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a transformation of cyclopropyl carbene a highly enantioselective three component reaction via trapping Oxonium ylide by imine
Tetrahedron, 2016Co-Authors: Mingfeng Li, Qing Zheng, Wenhao HuAbstract:Abstract A transformation of cyclopropyl carbene generated from 2-cyclopropyl-2-diazoacetate via Oxonium ylide was found by trapping the resulting ylide with imine. The asymmetric three-component reaction of cycloproyl diazoacetates, benzenemethanols and imines afforded a rapid and efficient method to synthesize complex cyclopropane derivatives with excellent diastereoselectivity and enantioselectivity.
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a facile access to polyfunctional oxygen containing heterocycles via intramolecularly formed protic Oxonium ylide trapping processes
ChemInform, 2014Co-Authors: Wenhao HuAbstract:Intramolecular trapping of Oxonium ylides, generated by Cu-catalyzed decomposition of diazoesters (I), with electron-deficient aldehydes and isatins yields 3-substituted 1,4-dioxan-2-ones with high diastereoselectivity.
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trapping of carboxylic Oxonium ylides with n boc imines for the facile synthesis of β amino alcohol derivatives
Synlett, 2014Co-Authors: Changwei Zhai, Jingjing Ji, Dong Xing, Yu Qian, Wenhao HuAbstract:A Rh2(OAc)4-catalyzed three-component reaction of carboxylic acids, α-diazoacetophenones, and N-Boc imines has been developed to efficiently produce β-amino alcohol derivatives. Oxonium ylides generated from carboxylic acids and metal carbenoids have been intercepted by electrophiles for the first time.
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a facile access to polyfunctional oxygen containing heterocycles via intramolecularly formed protic Oxonium ylide trapping processes
Chemistry-an Asian Journal, 2014Co-Authors: Wenhao HuAbstract:: Based on the assumption that intramolecularly formed protic Oxonium ylides could be trapped by electrophiles, transition-metal-catalyzed reactions of diazoesters bearing a primary hydroxy group with electron-deficient aldehydes and isatins were examined. Good to high chemo- and diastereoselectivities were achieved with reactions catalyzed by Cu(hfacac)2. The reactions were assumed to occur via tandem intramolecular protic Oxonium ylide formation and subsequent aldol-type addition. They not only provided an efficient entry to 3-substituted 1,4-dioxan-2-one heterocycles with at least one quaternary carbon center but also provided experimental evidence for a stepwise pathway for the transition-metal-catalyzed intramolecular O-H insertion of diazo compounds.
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trapping of Oxonium ylides with michael acceptors highly diastereoselective three component reactions of diazo compounds with alcohols and benzylidene meldrum s acids 4 oxo enoates
ChemInform, 2011Co-Authors: Jingjing Ji, Xia Zhang, Liqing Jiang, Wenhao HuAbstract:It is revealed that the title compounds are suitable Michael acceptors for interception of Oxonium ylides generated from diazo compounds and alcohols via a 1,4-addition mode.
V I Bregadze - One of the best experts on this subject based on the ideXlab platform.
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synthesis of Oxonium derivatives of the dodecahydro closo dodecaborate anion b12h12 2 tetramethylene Oxonium derivative of b12h12 2 as a convenient precursor for the synthesis of functional compounds for boron neutron capture therapy
Polyhedron, 2000Co-Authors: Igor B. Sivaev, Andrei A Semioshkin, Bernd Brellochs, Stefan Sjoberg, V I BregadzeAbstract:Direct synthesis of Oxonium derivatives of the dodecahydro-closo-dodecaborate anion is described and the reaction mechanism is discussed. Various derivatives of the [B12H12](2-) anion containing hydroxyl, amine, acid, and amino acid functions were prepare
Pipas Saha - One of the best experts on this subject based on the ideXlab platform.
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diastereoselective synthesis of substituted dihydropyrans via an Oxonium ene cyclization reaction
Organic and Biomolecular Chemistry, 2012Co-Authors: Pipas Saha, Priya Ghosh, Sabera Sultana, Anil K SaikiaAbstract:Substituted dihydropyrans can be efficiently synthesized in good yields with excellent diastereoselectivity from the reaction of aldehydes or epoxides and ethyl 3-alkyl-3-hydroxy-5-methylhex-5-enoate via an Oxonium–ene cyclization reaction catalyzed by trimethylsilyl trifluoromethanesulfonate (TMSOTf) under mild conditions.
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Diastereoselective synthesis of substituted dihydropyrans via an Oxonium–ene cyclization reaction
Organic and Biomolecular Chemistry, 2012Co-Authors: Pipas Saha, Priya Ghosh, Sabera Sultana, Anil K SaikiaAbstract:Substituted dihydropyrans can be efficiently synthesized in good yields with excellent diastereoselectivity from the reaction of aldehydes or epoxides and ethyl 3-alkyl-3-hydroxy-5-methylhex-5-enoate via an Oxonium–ene cyclization reaction catalyzed by trimethylsilyl trifluoromethanesulfonate (TMSOTf) under mild conditions.
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synthesis of 2 3 5 6 tetrasubstituted tetrahydropyrans via 3 5 Oxonium ene reaction
Organic and Biomolecular Chemistry, 2012Co-Authors: Pipas Saha, Anup Bhunia, Anil K SaikiaAbstract:An efficient method for the synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans has been developed from the reaction of aldehydes and ethyl 2-(1-hydroxyalkyl/hydroxy(phenyl)methyl)-5-methylhex-4-enoate using (3,5)-Oxonium-ene reaction promoted by boron trifluoride etherate in good yields under mild conditions.
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stereoselective synthesis of 6 oxabicyclo 3 2 1 octene via 3 5 Oxonium ene reaction
Tetrahedron, 2012Co-Authors: Pipas Saha, Anil K SaikiaAbstract:Abstract Oxabicyclo[3.2.1]octene can efficiently be synthesized by the reaction of (−)-terpinen-4-ol and aldehyde or epoxide catalyzed by indium triflate (In(OTf)3) in good yields. The reaction is stereoselective and proceeds via (3,5)-Oxonium-ene-type reaction.
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a novel synthesis of oxabicyclo 3 3 1 nonanone via 3 5 Oxonium ene reaction
Organic Letters, 2010Co-Authors: Pipas Saha, U C Reddy, Somasekhar Bondalapati, Anil K SaikiaAbstract:Oxabicyclo[3.3.1]nonanone can conveniently be prepared by the reaction of trans-p-menth-6-ene-2,8-diol and aldehyde or epoxide mediated by boron trifluoride etherate in good yields. The reaction proceeds via (3,5)-Oxonium−ene-type reaction.
