The Experts below are selected from a list of 3624 Experts worldwide ranked by ideXlab platform
Junliang Zhang - One of the best experts on this subject based on the ideXlab platform.
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Triflic Acid catalyzed enynes cyclization a new strategy beyond electrophilic π activation
Chemistry: A European Journal, 2016Co-Authors: Lu Liu, Junliang ZhangAbstract:The cyclization of enynes, catalyzed by a transition metal, represents a powerful tool to construct an array of cyclic compounds through electrophilic π-activation. In this paper, we disclose a new and efficient strategy for enynes cyclization catalyzed by Triflic Acid. The salient features of this transformation includes a broad substrate scope, metal free synthesis, open flask and mild conditions, good yields, ease of operation, low catalyst loading, and easy scale-up to gram scale. A preliminary mechanism study demonstrated that the activation model of the reaction was σ-activation, which is different from the transition-metal-catalyzed enynes cyclization. Our strategy affords a complementary method to the traditional strategies, which use transition-metal catalysts.
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Triflic Acid‐Catalyzed Enynes Cyclization: A New Strategy beyond Electrophilic π‐Activation
Chemistry (Weinheim an der Bergstrasse Germany), 2016Co-Authors: Lu Liu, Junliang ZhangAbstract:The cyclization of enynes, catalyzed by a transition metal, represents a powerful tool to construct an array of cyclic compounds through electrophilic π-activation. In this paper, we disclose a new and efficient strategy for enynes cyclization catalyzed by Triflic Acid. The salient features of this transformation includes a broad substrate scope, metal free synthesis, open flask and mild conditions, good yields, ease of operation, low catalyst loading, and easy scale-up to gram scale. A preliminary mechanism study demonstrated that the activation model of the reaction was σ-activation, which is different from the transition-metal-catalyzed enynes cyclization. Our strategy affords a complementary method to the traditional strategies, which use transition-metal catalysts.
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A Facile Route to Polysubstituted Naphthalenes and Benzofluorenols via Scandium Triflate- and Triflic Acid- Catalyzed Benzannulation of 2-(2-Alkynylarylidene)- 1,3-Dicarbonyl Compounds
Advanced Synthesis & Catalysis, 2010Co-Authors: Lu Liu, Lai Wei, Junliang ZhangAbstract:This paper describes an efficient scandium triflate- and Triflic Acid-catalyzed benzannulation of 2-(2-alkynylarylidene)-1,3-dicarbonyl compounds to afford polysubstituted naphthalenes and benzo[a]fluorenols. The product selectivity could be tuned by subtle choice of the catalyst. An unprecedented process between alkynes and ketones is also explored.
George A. Olah - One of the best experts on this subject based on the ideXlab platform.
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taming of superAcids pvp Triflic Acid as an effective solid Triflic Acid equivalent for friedel crafts hydroxyalkylation and acylation
Journal of Fluorine Chemistry, 2015Co-Authors: G Surya K Prakash, Farzaneh Paknia, Aditya Kulkarni, Arjun Narayanan, Fang Wang, Golam Rasul, Thomas Mathew, George A. OlahAbstract:Abstract The application of poly(4-vinylpyridine) supported trifluoromethanesulfonic Acid (PVP-TfOH, 1:10) as a convenient solid superAcid catalyst system in Friedel–Crafts reactions is described. In the presence of PVP-TfOH, one pot solvent-free synthesis of a wide variety of diarylacetic Acid derivatives was achieved by Friedel–Crafts hydroxyalkylation reaction of glyoxylic Acid with arenes under mild conditions. Acylation of both activated and deactivated aromatic compounds with acetyl chloride was also achieved using PVP-TfOH complex under solvent-free conditions at room temperature. As the polymer supported Triflic Acid was found to be a very efficient and an easy-to-handle solid Acid, it can be a useful addition to environmentally more adaptable strong Acid catalyst systems.
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Taming of superAcids: PVP-Triflic Acid as an effective solid Triflic Acid equivalent for Friedel–Crafts hydroxyalkylation and acylation
Journal of Fluorine Chemistry, 2015Co-Authors: G. K. Surya Prakash, Farzaneh Paknia, Aditya Kulkarni, Arjun Narayanan, Fang Wang, Golam Rasul, Thomas Mathew, George A. OlahAbstract:Abstract The application of poly(4-vinylpyridine) supported trifluoromethanesulfonic Acid (PVP-TfOH, 1:10) as a convenient solid superAcid catalyst system in Friedel–Crafts reactions is described. In the presence of PVP-TfOH, one pot solvent-free synthesis of a wide variety of diarylacetic Acid derivatives was achieved by Friedel–Crafts hydroxyalkylation reaction of glyoxylic Acid with arenes under mild conditions. Acylation of both activated and deactivated aromatic compounds with acetyl chloride was also achieved using PVP-TfOH complex under solvent-free conditions at room temperature. As the polymer supported Triflic Acid was found to be a very efficient and an easy-to-handle solid Acid, it can be a useful addition to environmentally more adaptable strong Acid catalyst systems.
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Trifluoromethanesulfonic (Triflic) Acid catalyzed transformations of .alpha.-hydroxy carbonyl compounds
The Journal of Organic Chemistry, 1991Co-Authors: George A. OlahAbstract:Triflic Acid catalyzed reaction of 2-hydroxy-2-adamantanecarboxylic Acid results via ionizative decarbonylation in the formation of adamantanone. Under carbon monoxide pressure pinacol-type rearrangement gives 4,5-homoadamantanedione. Reaction of a series of α-hydroxy ketones result in fragmentation, deprotonation, and cyclization, respectively. The reactions and their suggested mechanism are discussed
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Synthetic methods and reactions. 157. Reductive alkylation and reduction of tertiary, secondary, and benzylic alcohols with trimethyl-(triethyl-, and triisopropyl)boron/trifluoromethanesulfonic (Triflic) Acid
The Journal of Organic Chemistry, 1991Co-Authors: George A. Olah, Omar FarooqAbstract:Tertiary, secondary, and benzylic alcohols were reductively alkylated and reduced with trimethyl-, triethyl-, and triisopropylboron/trifluoromethanesulfonic (Triflic) Acid. A postulated mechanism for the reactions is discussed
Abid Shaikh - One of the best experts on this subject based on the ideXlab platform.
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Triflic Acid-Catalyzed C(sp3)—H Functionalization of 2-Methyl Azaarenes with a α-Trifluoromethyl Imino Ester.
ChemInform, 2015Co-Authors: Mark Blocker, Supriya Immaneni, Abid ShaikhAbstract:Triflic Acid catalyzes both the functionalization of 2-alkyl azaarenes and concomitant N-deprotection of imino ester (II).
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Triflic Acid catalyzed csp3 hcsp3 h functionalization of 2 methyl azaarenes with a α trifluoromethyl imino ester
Tetrahedron Letters, 2014Co-Authors: Mark Blocker, Supriya Immaneni, Abid ShaikhAbstract:A Bronsted Acid promoted Csp3–HCsp3–H functionalization of 2-alkyl azaarenes with α-trifluoromethylated imino ester is described. A catalytic amount of Triflic Acid provided straightforward access to the corresponding trifluoromethylated amino esters via concomitant in situ one step N-alkyl deprotection. On further hydrolysis of ester, synthesis of quinoline derived unnatural trifluoromethylated amino Acids has been achieved in a short and efficient manner.
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Triflic Acid-catalyzed Csp3–HCsp3–H functionalization of 2-methyl azaarenes with a α-trifluoromethyl imino ester
Tetrahedron Letters, 2014Co-Authors: Mark Blocker, Supriya Immaneni, Abid ShaikhAbstract:A Bronsted Acid promoted Csp3–HCsp3–H functionalization of 2-alkyl azaarenes with α-trifluoromethylated imino ester is described. A catalytic amount of Triflic Acid provided straightforward access to the corresponding trifluoromethylated amino esters via concomitant in situ one step N-alkyl deprotection. On further hydrolysis of ester, synthesis of quinoline derived unnatural trifluoromethylated amino Acids has been achieved in a short and efficient manner.
Yoshinori Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Triflic Acid catalyzed cascade cyclization of arenyl enynes via acetylene cation cyclization and friedel crafts type reaction
Tetrahedron Letters, 2011Co-Authors: Tienan Jin, Junichi Uchiyama, Masafumi Himuro, Yoshinori YamamotoAbstract:Abstract A novel Triflic Acid-catalyzed cascade cyclization of arenyl 1,7-enynes through acetylene-cation cyclization followed by Friedel–Crafts reaction has been described. Various fused poly carbocycles can be obtained in good to high yields under mild reaction conditions.
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Triflic Acid-catalyzed cascade cyclization of arenyl enynes via acetylene-cation cyclization and Friedel–Crafts type reaction
Tetrahedron Letters, 2011Co-Authors: Tienan Jin, Junichi Uchiyama, Masafumi Himuro, Yoshinori YamamotoAbstract:Abstract A novel Triflic Acid-catalyzed cascade cyclization of arenyl 1,7-enynes through acetylene-cation cyclization followed by Friedel–Crafts reaction has been described. Various fused poly carbocycles can be obtained in good to high yields under mild reaction conditions.
Mark Blocker - One of the best experts on this subject based on the ideXlab platform.
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Triflic Acid-Catalyzed C(sp3)—H Functionalization of 2-Methyl Azaarenes with a α-Trifluoromethyl Imino Ester.
ChemInform, 2015Co-Authors: Mark Blocker, Supriya Immaneni, Abid ShaikhAbstract:Triflic Acid catalyzes both the functionalization of 2-alkyl azaarenes and concomitant N-deprotection of imino ester (II).
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Triflic Acid catalyzed csp3 hcsp3 h functionalization of 2 methyl azaarenes with a α trifluoromethyl imino ester
Tetrahedron Letters, 2014Co-Authors: Mark Blocker, Supriya Immaneni, Abid ShaikhAbstract:A Bronsted Acid promoted Csp3–HCsp3–H functionalization of 2-alkyl azaarenes with α-trifluoromethylated imino ester is described. A catalytic amount of Triflic Acid provided straightforward access to the corresponding trifluoromethylated amino esters via concomitant in situ one step N-alkyl deprotection. On further hydrolysis of ester, synthesis of quinoline derived unnatural trifluoromethylated amino Acids has been achieved in a short and efficient manner.
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Triflic Acid-catalyzed Csp3–HCsp3–H functionalization of 2-methyl azaarenes with a α-trifluoromethyl imino ester
Tetrahedron Letters, 2014Co-Authors: Mark Blocker, Supriya Immaneni, Abid ShaikhAbstract:A Bronsted Acid promoted Csp3–HCsp3–H functionalization of 2-alkyl azaarenes with α-trifluoromethylated imino ester is described. A catalytic amount of Triflic Acid provided straightforward access to the corresponding trifluoromethylated amino esters via concomitant in situ one step N-alkyl deprotection. On further hydrolysis of ester, synthesis of quinoline derived unnatural trifluoromethylated amino Acids has been achieved in a short and efficient manner.
