The Experts below are selected from a list of 1830 Experts worldwide ranked by ideXlab platform
Yong Rok Lee - One of the best experts on this subject based on the ideXlab platform.
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Synergistic Indium and Silver Dual Catalysis: A Regioselective [2 + 2 + 1]-Oxidative N‑Annulation Approach for the Diverse and Polyfunctionalized N‑Arylpyrazoles
2018Co-Authors: Raju S. Thombal, Yong Rok LeeAbstract:Indium(III)/silver(I)-catalyzed [2 + 2 + 1] annulation of arylhydrazine hydrochlorides with β-enamino esters via multicomponent reactions for the construction of diverse and multisubstituted N-arylpyrazoles has been demonstrated. The Oxidative Cycloaddition proceeds via a cascade triple Michael addition/elimination/air oxidation. This novel protocol provides a rapid and efficient synthetic route to various 3,4-diester-substituted N-arylpyrazoles. The synthesized compounds are further utilized for various synthetic transformations
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one step synthesis of tetrahydroindoles by ceric iv ammonium nitrate promoted Oxidative Cycloaddition of enaminones and vinyl ethers
Tetrahedron, 2014Co-Authors: Yong Rok Lee, Sung Hong KimAbstract:Abstract A new and general one-step procedure to synthesize a variety of biologically interesting tetrahydroindole derivatives was successfully devised by reacting various β-enaminones with vinyl ethers in the presence of ceric(IV) ammonium nitrate as promoter. This novel synthetic method provides a facile and promising strategy to various tetrahydroindole derivatives in moderate to good yields.
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efficient synthesis of dihydrofurans with sulfide groups by ceric iv ammonium nitrate mediated Oxidative Cycloaddition of 1 3 dicarbonyl compounds to vinyl sulfides application to the synthesis of benzo b naphtho 2 3 d furan 6 11 dione and first tota
Synthesis, 2003Co-Authors: Yong Rok Lee, Keon Yong Kang, Gun Joon Lee, Won Kyong LeeAbstract:Ceric(IV) ammonium nitrate-mediated Oxidative Cycloaddition of 1,3-dicarbonyls to vinyl sulfides afforded substituted dihydrofurans with sulfide groups in moderate yields. This new synthetic method has been applied to thesynthesis of benzo[b]naphtho[2,3-d]furan-6,11-dione and furanoflavone natural products such as millettocalyxins C and pongol methyl ether.
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efficient synthesis of dihydrofuroquinolinones and furoquinolinones by silver i celite promoted Oxidative Cycloaddition
Tetrahedron, 2000Co-Authors: Yong Rok Lee, Byung So Kim, Hyuk Il KweonAbstract:Abstract A new synthesis of dihydrofuroquinolinones and furoquinolinones is achieved from 4-hydroxy-2-quinolones and a variety of olefins in the presence of Ag2CO3/Celite in moderate yields. The new method has been applied to the synthesis of the pseudoisodictamnine.
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Ceric Ammonium Nitrate (CAN)-Mediated Oxidative Cycloaddition of 1,3-Dicarbonyls to Conjugated Compounds. Efficient Synthesis of Dihydrofurans, Dihydrofurocoumarins, Dihydrofuroquinolinones, Dihydrofurophenalenones, and Furonaphthoquinone Natural Pro
Tetrahedron, 2000Co-Authors: Yong Rok Lee, Byung So Kim, Dae Hwan KimAbstract:Abstract Ceric ammonium nitrate-mediated Oxidative Cycloaddition of 1,3-dicarbonyls to conjugated compounds afforded substituted dihydrofurans, dihydrofurocoumarins, dihydrofuroquinolinones, and dihydrofurophenalenones in moderate yields. This new synthetic method has been applied to the synthesis of furonaphthoquinone natural products.
Viktor V Zhdankin - One of the best experts on this subject based on the ideXlab platform.
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synthesis of oxazoline and oxazole derivatives by hypervalent iodine mediated Oxidative Cycloaddition reactions
Synthesis, 2020Co-Authors: Akira Yoshimura, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:Organohypervalent iodine reagents are widely used for the preparation of various oxazolines, oxazoles, isoxazolines, and isoxazoles. In the formation of these heterocyclic compounds, hypervalent iodine species can serve as the activating reagents for various substrates, as well as the heteroatom donor reagents. In recent research, both chemical and electrochemical approaches toward generation of hypervalent iodine species have been utilized. The in situ generated active species can react with appropriate substrates to give the corresponding heterocyclic products. In this short review, we summarize the hypervalent-iodine-mediated preparation of oxazolines, oxazoles, isoxazolines, and isoxazoles starting from various substrates. 1 Introduction 2 Synthesis of Oxazolines 3 Synthesis of Oxazoles 4 Synthesis of Isoxazolines 5 Synthesis of Isoxazoles 6 Conclusion
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Oxidative Cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine iii reagents
Beilstein Journal of Organic Chemistry, 2018Co-Authors: Hisato Shimizu, Akira Yoshimura, Viktor V Zhdankin, Keiichi Noguchi, Victor N Nemykin, Akio SaitoAbstract:[Bis(trifluoroacetoxy)iodo]benzene (BTI) and (diacetoxyiodo)benzene (DIB) efficiently promote the formation of acylnitroso species from hydroxamic acids in the presence of various dienes to give the corresponding hetero-Diels-Alder (HDA) adducts in moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the Oxidative dearomatization of guaiacols.
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Oxidative Cycloaddition of aldoximes with maleimides using catalytic hydroxy aryl iodonium species
Advanced Synthesis & Catalysis, 2016Co-Authors: Akira Yoshimura, Khiem C Nguyen, Gregory T Rohde, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:A mild catalytic procedure for the efficient Oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and 1H NMR spectroscopy.
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Oxidative Cycloaddition of aldoximes with maleimides using catalytic hydroxy aryl iodonium species
Advanced Synthesis & Catalysis, 2016Co-Authors: Akira Yoshimura, Khiem C Nguyen, Gregory T Rohde, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:A mild catalytic procedure for the efficient Oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and 1H NMR spectroscopy.
Akira Yoshimura - One of the best experts on this subject based on the ideXlab platform.
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synthesis of oxazoline and oxazole derivatives by hypervalent iodine mediated Oxidative Cycloaddition reactions
Synthesis, 2020Co-Authors: Akira Yoshimura, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:Organohypervalent iodine reagents are widely used for the preparation of various oxazolines, oxazoles, isoxazolines, and isoxazoles. In the formation of these heterocyclic compounds, hypervalent iodine species can serve as the activating reagents for various substrates, as well as the heteroatom donor reagents. In recent research, both chemical and electrochemical approaches toward generation of hypervalent iodine species have been utilized. The in situ generated active species can react with appropriate substrates to give the corresponding heterocyclic products. In this short review, we summarize the hypervalent-iodine-mediated preparation of oxazolines, oxazoles, isoxazolines, and isoxazoles starting from various substrates. 1 Introduction 2 Synthesis of Oxazolines 3 Synthesis of Oxazoles 4 Synthesis of Isoxazolines 5 Synthesis of Isoxazoles 6 Conclusion
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Oxidative Cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine iii reagents
Beilstein Journal of Organic Chemistry, 2018Co-Authors: Hisato Shimizu, Akira Yoshimura, Viktor V Zhdankin, Keiichi Noguchi, Victor N Nemykin, Akio SaitoAbstract:[Bis(trifluoroacetoxy)iodo]benzene (BTI) and (diacetoxyiodo)benzene (DIB) efficiently promote the formation of acylnitroso species from hydroxamic acids in the presence of various dienes to give the corresponding hetero-Diels-Alder (HDA) adducts in moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the Oxidative dearomatization of guaiacols.
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Oxidative Cycloaddition of aldoximes with maleimides using catalytic hydroxy aryl iodonium species
Advanced Synthesis & Catalysis, 2016Co-Authors: Akira Yoshimura, Khiem C Nguyen, Gregory T Rohde, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:A mild catalytic procedure for the efficient Oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and 1H NMR spectroscopy.
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Oxidative Cycloaddition of aldoximes with maleimides using catalytic hydroxy aryl iodonium species
Advanced Synthesis & Catalysis, 2016Co-Authors: Akira Yoshimura, Khiem C Nguyen, Gregory T Rohde, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:A mild catalytic procedure for the efficient Oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and 1H NMR spectroscopy.
Akio Saito - One of the best experts on this subject based on the ideXlab platform.
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synthesis of oxazoline and oxazole derivatives by hypervalent iodine mediated Oxidative Cycloaddition reactions
Synthesis, 2020Co-Authors: Akira Yoshimura, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:Organohypervalent iodine reagents are widely used for the preparation of various oxazolines, oxazoles, isoxazolines, and isoxazoles. In the formation of these heterocyclic compounds, hypervalent iodine species can serve as the activating reagents for various substrates, as well as the heteroatom donor reagents. In recent research, both chemical and electrochemical approaches toward generation of hypervalent iodine species have been utilized. The in situ generated active species can react with appropriate substrates to give the corresponding heterocyclic products. In this short review, we summarize the hypervalent-iodine-mediated preparation of oxazolines, oxazoles, isoxazolines, and isoxazoles starting from various substrates. 1 Introduction 2 Synthesis of Oxazolines 3 Synthesis of Oxazoles 4 Synthesis of Isoxazolines 5 Synthesis of Isoxazoles 6 Conclusion
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Oxidative Cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine iii reagents
Beilstein Journal of Organic Chemistry, 2018Co-Authors: Hisato Shimizu, Akira Yoshimura, Viktor V Zhdankin, Keiichi Noguchi, Victor N Nemykin, Akio SaitoAbstract:[Bis(trifluoroacetoxy)iodo]benzene (BTI) and (diacetoxyiodo)benzene (DIB) efficiently promote the formation of acylnitroso species from hydroxamic acids in the presence of various dienes to give the corresponding hetero-Diels-Alder (HDA) adducts in moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the Oxidative dearomatization of guaiacols.
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Oxidative Cycloaddition of aldoximes with maleimides using catalytic hydroxy aryl iodonium species
Advanced Synthesis & Catalysis, 2016Co-Authors: Akira Yoshimura, Khiem C Nguyen, Gregory T Rohde, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:A mild catalytic procedure for the efficient Oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and 1H NMR spectroscopy.
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Oxidative Cycloaddition of aldoximes with maleimides using catalytic hydroxy aryl iodonium species
Advanced Synthesis & Catalysis, 2016Co-Authors: Akira Yoshimura, Khiem C Nguyen, Gregory T Rohde, Akio Saito, Mekhman S Yusubov, Viktor V ZhdankinAbstract:A mild catalytic procedure for the efficient Oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and 1H NMR spectroscopy.
Tomislav Rovis - One of the best experts on this subject based on the ideXlab platform.
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rhodium catalyzed Oxidative Cycloaddition of benzamides and alkynes via c h n h activation
ChemInform, 2011Co-Authors: Todd K Hyster, Tomislav RovisAbstract:In the presence of a copper(II) salt as oxidant, benzamides as well as heterocyclic carboxamides undergo the title reaction with a variety of internal alkynes to give isoquinolinones or the corresponding heteroaryl-fused pyridine analogues.
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Rhodium-Catalyzed Oxidative Cycloaddition of Benzamides and Alkynes via C−H/N−H Activation
Journal of the American Chemical Society, 2010Co-Authors: Todd K Hyster, Tomislav RovisAbstract:The Oxidative Cycloaddition of benzamides and alkynes has been developed. The reaction utilizes Rh(III) catalysts in the presence of Cu(II) oxidants, and is proposed to proceed by N−H metalation of the amide followed by ortho C−H activation. The resultant rhodacycle undergoes alkyne insertion to form isoquinolones in good yield. The reaction is tolerant of extensive substitution on the amide, alkyne, and arene, including halides, silyl ethers, and unprotected aldehydes as substituents. Unsymmetrical alkynes proceed with excellent regioselectivity, and heteroaryl carboxamides are tolerated leading to intriguing scaffolds for medicinal chemistry. A series of competition experiments shed further light on the mechanism of the transformation and reasons for selectivity.
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rhodium catalyzed Oxidative Cycloaddition of benzamides and alkynes via c h n h activation
Journal of the American Chemical Society, 2010Co-Authors: Todd K Hyster, Tomislav RovisAbstract:The Oxidative Cycloaddition of benzamides and alkynes has been developed. The reaction utilizes Rh(III) catalysts in the presence of Cu(II) oxidants, and is proposed to proceed by N−H metalation of the amide followed by ortho C−H activation. The resultant rhodacycle undergoes alkyne insertion to form isoquinolones in good yield. The reaction is tolerant of extensive substitution on the amide, alkyne, and arene, including halides, silyl ethers, and unprotected aldehydes as substituents. Unsymmetrical alkynes proceed with excellent regioselectivity, and heteroaryl carboxamides are tolerated leading to intriguing scaffolds for medicinal chemistry. A series of competition experiments shed further light on the mechanism of the transformation and reasons for selectivity.
