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Mikhail S. Novikov - One of the best experts on this subject based on the ideXlab platform.
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buchner reaction azirine modification approach toward cycloheptatriene containing nitrogen heterocyclic scaffolds
Journal of Organic Chemistry, 2021Co-Authors: Ekaterina E. Galenko, Mikhail S. Novikov, Mariya A Kryukova, Vladimir A Bodunov, Alexander F. KhlebnikovAbstract:The reaction conditions for the Buchner reaction of 2-(diazoacetyl)-2H-Azirines with benzene leading to 2-(cyclohepta-2,4,6-trien-1-yl)-2H-Azirines have been found. The azirine fragment of these compounds was subsequently used to prepare 5-(cyclohepta-2,4,6-trien-1-yl)isoxazoles and α-(cyclohepta-2,4,6-triene-1-ylcarbonyl)-1H-pyrroles. NMR and DFT calculations showed that the cycloheptatriene-norcaradiene valence isomerization in the corresponding moieties of synthesized azirines, isoxazoles, and pyrroles is very fast at room temperature. Cycloheptatriene valence isomer predominates in azirines and pyrroles, while 5-(cycloheptatrienyl)isoxazoles exist in a pure cycloheptatriene form at 25 °C in chloroform solution. In accordance with the X-ray analysis, two of the synthesized pyrroles crystallized as norcaradiene isomers from a solution of equilibrium mixture of valence isomers. Reductive isoxazole ring opening using the Mo(CO)6/H2O reductive system afforded (Z)-3-amino-3-aryl-1-(cyclohepta-2,4,6-trien-1-yl)prop-2-en-1-ones, which are pure cycloheptatriene isomers. α-(Cycloheptatrieneylcarbonyl)-1H-pyrroles were transformed into the α-(benzylcarbonyl)-1H-pyrroles under cooperative TFA/Rh2(TFA)4 catalysis.
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Nucleophile-Induced Rearrangement of 2H‑Azirine-2-carbonyl Azides to 2‑(1H‑Tetrazol-1-yl)acetic Acid Derivatives
'American Chemical Society (ACS)', 2021Co-Authors: Nikita I. Efimenko, Mikhail S. Novikov, Olesya A. Tomashenko, Dar’ya V. Spiridonova, Alexander F. KhlebnikovAbstract:2H-Azirine-2-carbonyl azides undergo a rearrangement into derivatives of 2-(1H-tetrazol-1-yl)acetic acid when interacting with O- and S-nucleophiles at room temperature. The reaction is catalyzed by tertiary amines or hydrazoic acid. The reaction with primary alcohols and phenols gives alkyl/aryl 2-(1H-tetrazol-1-yl)acetates. Thiophenols react with 2H-Azirine-2-carbonyl azides to afford S-aryl 2-(1H-tetrazol-1-yl)ethanethioates. The mechanism of the nucleophile-induced rearrangement of 2H-Azirine-2-carbonyl azides is discussed on the basis of DFT calculations as well as kinetic and 15N labeling experiments
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regiodivergent synthesis of butenolide based α and β amino acid derivatives via base controlled azirine ring expansion
Organic Letters, 2020Co-Authors: Pavel A Sakharov, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Mikhail S. NovikovAbstract:A method for the preparation of 5-aminobutenolides from 2-bromo-2H-Azirine-2-carboxylic esters/amides with arylacetic acids has been developed. The reaction regioselectivity can be switched by a change of the basic catalyst, making it possible to prepare both butenolide-based α- and β-amino acid derivatives. The change in the regioselectivity is interpreted in terms of the stability and reactivity of the enolates formed during the SN2' substitution of the bromine in the azirine by the carboxylate ion.
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1 2h azirine 2 carbonyl benzotriazoles building blocks for the synthesis of pyrrole containing heterocycles
Organic and Biomolecular Chemistry, 2020Co-Authors: Ekaterina E. Galenko, Mikhail S. Novikov, Vladimir A Bodunov, Firuza M Shakirova, Alexander F. KhlebnikovAbstract:A one-pot method was developed for the preparation of 2H-Azirine-2-carbonylbenzotriazoles, formed by the reaction of benzotriazole with 2H-Azirine-2-carbonyl chlorides, which were generated by the Fe(ii)-catalyzed isomerization of 5-chloroisoxazoles. The Co(ii)-catalyzed reaction of 2H-Azirine-2-carbonylbenzotriazoles with 1,3-diketones provides 2-((benzotriazol-1-yl)carbonyl)pyrroles in moderate to good yields. Base-promoted annulations of 2-((benzotriazol-1-yl)carbonyl)pyrroles with aldehydes, ketones, isocyanates and isothiocyanates afford various substituted pyrrolo[1,2-c]oxazole and 1H-pyrrolo[1,2-c]imidazole derivatives in moderate to high yields. The 6-acyl group of these adducts can be removed by triflic acid, giving further new pyrrolo-fused O- and N-heterocycles, such as 6-unsubstituted pyrrolo[1,2-c]oxazol-1(3H)-one and 1H-pyrrolo[1,2-c]imidazole-1,3(2H)-dione, while the 6-acetyl substituent of 1H-pyrrolo[1,2-c]imidazole-1,3(2H)-dione, when treated with POCl3/pyridine, is transformed into the 6-ethynyl substituent.
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2h azirine 2 carbonyl azides preparation and use as n heterocyclic building blocks
Journal of Organic Chemistry, 2020Co-Authors: Liya D. Funt, Mikhail S. Novikov, Yulia V Krivolapova, Olesya V Khoroshilova, Alexander F. KhlebnikovAbstract:2H-Azirine-2-carbonyl azides, new reactive heterocyclic building blocks, were synthesized in high yield by the reaction of sodium azide with 2H-Azirine-2-carbonyl chlorides, generated by the Fe(II)-catalyzed isomerization of 5-chloroisoxazoles. 2-(Azidocarbonyl)-1H-pyrroles, prepared by the Ni(II)-catalyzed reaction of 2-(azidocarbonyl)-2H-Azirines with 1,3-diketones, easily undergo the Curtius rearrangement in boiling tBuOH to give Boc-protected α-aminopyrroles in high yield. Heating of 2-(azidocarbonyl)-1H-pyrroles for a short time in inert solvents leads to the high-yield formation of benzo- and hetero-fused 1H-pyrrolo[2,3-b]pyridin-6(7H)-ones, which are formed via a 6π electrocyclization involving the vicinal aryl or hetaryl substituent and the N═C bond of isocyanate, generated by the Curtius rearrangement of the azidocarbonyl group. The Pd-catalyzed cross-coupling reaction of 1-acetyl-2-methyl-3H-pyrrolo[2,3-c]isoquinolin-5-yl triflate, easily prepared from the corresponding pyrroloisoquinolone, leads to variously 5-substituted 3H-pyrrolo[2,3-c]isoquinolines in excellent yields.
Alexander F. Khlebnikov - One of the best experts on this subject based on the ideXlab platform.
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buchner reaction azirine modification approach toward cycloheptatriene containing nitrogen heterocyclic scaffolds
Journal of Organic Chemistry, 2021Co-Authors: Ekaterina E. Galenko, Mikhail S. Novikov, Mariya A Kryukova, Vladimir A Bodunov, Alexander F. KhlebnikovAbstract:The reaction conditions for the Buchner reaction of 2-(diazoacetyl)-2H-Azirines with benzene leading to 2-(cyclohepta-2,4,6-trien-1-yl)-2H-Azirines have been found. The azirine fragment of these compounds was subsequently used to prepare 5-(cyclohepta-2,4,6-trien-1-yl)isoxazoles and α-(cyclohepta-2,4,6-triene-1-ylcarbonyl)-1H-pyrroles. NMR and DFT calculations showed that the cycloheptatriene-norcaradiene valence isomerization in the corresponding moieties of synthesized azirines, isoxazoles, and pyrroles is very fast at room temperature. Cycloheptatriene valence isomer predominates in azirines and pyrroles, while 5-(cycloheptatrienyl)isoxazoles exist in a pure cycloheptatriene form at 25 °C in chloroform solution. In accordance with the X-ray analysis, two of the synthesized pyrroles crystallized as norcaradiene isomers from a solution of equilibrium mixture of valence isomers. Reductive isoxazole ring opening using the Mo(CO)6/H2O reductive system afforded (Z)-3-amino-3-aryl-1-(cyclohepta-2,4,6-trien-1-yl)prop-2-en-1-ones, which are pure cycloheptatriene isomers. α-(Cycloheptatrieneylcarbonyl)-1H-pyrroles were transformed into the α-(benzylcarbonyl)-1H-pyrroles under cooperative TFA/Rh2(TFA)4 catalysis.
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Nucleophile-Induced Rearrangement of 2H‑Azirine-2-carbonyl Azides to 2‑(1H‑Tetrazol-1-yl)acetic Acid Derivatives
'American Chemical Society (ACS)', 2021Co-Authors: Nikita I. Efimenko, Mikhail S. Novikov, Olesya A. Tomashenko, Dar’ya V. Spiridonova, Alexander F. KhlebnikovAbstract:2H-Azirine-2-carbonyl azides undergo a rearrangement into derivatives of 2-(1H-tetrazol-1-yl)acetic acid when interacting with O- and S-nucleophiles at room temperature. The reaction is catalyzed by tertiary amines or hydrazoic acid. The reaction with primary alcohols and phenols gives alkyl/aryl 2-(1H-tetrazol-1-yl)acetates. Thiophenols react with 2H-Azirine-2-carbonyl azides to afford S-aryl 2-(1H-tetrazol-1-yl)ethanethioates. The mechanism of the nucleophile-induced rearrangement of 2H-Azirine-2-carbonyl azides is discussed on the basis of DFT calculations as well as kinetic and 15N labeling experiments
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regiodivergent synthesis of butenolide based α and β amino acid derivatives via base controlled azirine ring expansion
Organic Letters, 2020Co-Authors: Pavel A Sakharov, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Mikhail S. NovikovAbstract:A method for the preparation of 5-aminobutenolides from 2-bromo-2H-Azirine-2-carboxylic esters/amides with arylacetic acids has been developed. The reaction regioselectivity can be switched by a change of the basic catalyst, making it possible to prepare both butenolide-based α- and β-amino acid derivatives. The change in the regioselectivity is interpreted in terms of the stability and reactivity of the enolates formed during the SN2' substitution of the bromine in the azirine by the carboxylate ion.
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1 2h azirine 2 carbonyl benzotriazoles building blocks for the synthesis of pyrrole containing heterocycles
Organic and Biomolecular Chemistry, 2020Co-Authors: Ekaterina E. Galenko, Mikhail S. Novikov, Vladimir A Bodunov, Firuza M Shakirova, Alexander F. KhlebnikovAbstract:A one-pot method was developed for the preparation of 2H-Azirine-2-carbonylbenzotriazoles, formed by the reaction of benzotriazole with 2H-Azirine-2-carbonyl chlorides, which were generated by the Fe(ii)-catalyzed isomerization of 5-chloroisoxazoles. The Co(ii)-catalyzed reaction of 2H-Azirine-2-carbonylbenzotriazoles with 1,3-diketones provides 2-((benzotriazol-1-yl)carbonyl)pyrroles in moderate to good yields. Base-promoted annulations of 2-((benzotriazol-1-yl)carbonyl)pyrroles with aldehydes, ketones, isocyanates and isothiocyanates afford various substituted pyrrolo[1,2-c]oxazole and 1H-pyrrolo[1,2-c]imidazole derivatives in moderate to high yields. The 6-acyl group of these adducts can be removed by triflic acid, giving further new pyrrolo-fused O- and N-heterocycles, such as 6-unsubstituted pyrrolo[1,2-c]oxazol-1(3H)-one and 1H-pyrrolo[1,2-c]imidazole-1,3(2H)-dione, while the 6-acetyl substituent of 1H-pyrrolo[1,2-c]imidazole-1,3(2H)-dione, when treated with POCl3/pyridine, is transformed into the 6-ethynyl substituent.
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2h azirine 2 carbonyl azides preparation and use as n heterocyclic building blocks
Journal of Organic Chemistry, 2020Co-Authors: Liya D. Funt, Mikhail S. Novikov, Yulia V Krivolapova, Olesya V Khoroshilova, Alexander F. KhlebnikovAbstract:2H-Azirine-2-carbonyl azides, new reactive heterocyclic building blocks, were synthesized in high yield by the reaction of sodium azide with 2H-Azirine-2-carbonyl chlorides, generated by the Fe(II)-catalyzed isomerization of 5-chloroisoxazoles. 2-(Azidocarbonyl)-1H-pyrroles, prepared by the Ni(II)-catalyzed reaction of 2-(azidocarbonyl)-2H-Azirines with 1,3-diketones, easily undergo the Curtius rearrangement in boiling tBuOH to give Boc-protected α-aminopyrroles in high yield. Heating of 2-(azidocarbonyl)-1H-pyrroles for a short time in inert solvents leads to the high-yield formation of benzo- and hetero-fused 1H-pyrrolo[2,3-b]pyridin-6(7H)-ones, which are formed via a 6π electrocyclization involving the vicinal aryl or hetaryl substituent and the N═C bond of isocyanate, generated by the Curtius rearrangement of the azidocarbonyl group. The Pd-catalyzed cross-coupling reaction of 1-acetyl-2-methyl-3H-pyrrolo[2,3-c]isoquinolin-5-yl triflate, easily prepared from the corresponding pyrroloisoquinolone, leads to variously 5-substituted 3H-pyrrolo[2,3-c]isoquinolines in excellent yields.
Galina L. Starova - One of the best experts on this subject based on the ideXlab platform.
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synthesis of 2 di tri tetraazolyl 2h azirine 2 carboxylates by halogen substitution evidence for an sn2 sn2 cascade mechanism
Journal of Organic Chemistry, 2018Co-Authors: Anastasiya V. Agafonova, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Galina L. Starova, Ilia A. Smetanin, Mikhail S. NovikovAbstract:An effective and operationally simple method for the preparation of methyl 2-(di/tri/tetraazol-1-yl)-2H-Azirine-2-carboxylates from accessible methyl 2-halo-2H-Azirine-2-carboxylates and NH-azoles has been developed. The azoles having enhanced NH acidity, react with 2-halo-2H-Azirines in the presence of Et3N in a deprotonated form, while the azoles having highly nucleophilic sp2 nitrogen react in neutral form. According to the DFT calculations, the substitution of the halogen by the azole proceeds via an SN2′-SN2′ cascade, with the initial conjugate substitution of the halogen being the rate-determining step. The formation of 2,3-dipyrazolylaziridines in the reaction of pyrazole provides experimental evidence for the cascade mechanism of the reaction.
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fe ii catalyzed isomerization of 5 chloroisoxazoles to 2h azirine 2 carbonyl chlorides as a key stage in the synthesis of pyrazole nitrogen heterocycle dyads
Journal of Organic Chemistry, 2018Co-Authors: Kirill I Mikhailov, Ekaterina E. Galenko, Mikhail S. Novikov, Alexey V. Galenko, Alexander Yu. Ivanov, Galina L. Starova, Alexander F. KhlebnikovAbstract:2-(1H-Pyrazol-1-ylcarbonyl)-2H-Azirines were synthesized by in situ trapping of 2H-Azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles, with pyrazoles. According to DFT calculations, the selectivity of nucleophilic substitution at the carbonyl group of 2H-Azirine-2-carbonyl chloride by a pyrazole nucleophile, which is a mixture of two tautomers, is controlled by thermodynamic factors. 2-(1H-Pyrazol-1-ylcarbonyl)-2H-Azirines are excellent precursors for the preparation of two other pyrazole–nitrogen heterocycle dyads: 5-(1H-pyrazol-1-yl)oxazoles by photolysis and 1-(1H-pyrrol-2-ylcarbonyl)-1H-pyrazoles by a Ni(II)-catalyzed reaction with 1,3-dicarbonyl compounds. 5-(1H-Pyrazol-1-yl)oxazoles show strong emission in acetonitrile at 360–410 nm with high quantum yields.
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Fe(II)-Catalyzed Isomerization of 5‑Chloroisoxazoles to 2H‑Azirine-2-carbonyl Chlorides as a Key Stage in the Synthesis of Pyrazole–Nitrogen Heterocycle Dyads
2018Co-Authors: Kirill I. Mikhailov, Ekaterina E. Galenko, Mikhail S. Novikov, Alexey V. Galenko, Alexander Yu. Ivanov, Galina L. Starova, Alexander F. KhlebnikovAbstract:2-(1H-Pyrazol-1-ylcarbonyl)-2H-Azirines were synthesized by in situ trapping of 2H-Azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles, with pyrazoles. According to DFT calculations, the selectivity of nucleophilic substitution at the carbonyl group of 2H-Azirine-2-carbonyl chloride by a pyrazole nucleophile, which is a mixture of two tautomers, is controlled by thermodynamic factors. 2-(1H-Pyrazol-1-ylcarbonyl)-2H-Azirines are excellent precursors for the preparation of two other pyrazole–nitrogen heterocycle dyads: 5-(1H-pyrazol-1-yl)oxazoles by photolysis and 1-(1H-pyrrol-2-ylcarbonyl)-1H-pyrazoles by a Ni(II)-catalyzed reaction with 1,3-dicarbonyl compounds. 5-(1H-Pyrazol-1-yl)oxazoles show strong emission in acetonitrile at 360–410 nm with high quantum yields
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Synthesis of 2‑(Di/tri/tetraazolyl)‑2H‑azirine-2-carboxylates by Halogen Substitution: Evidence for an SN2′‑SN2′ Cascade Mechanism
2018Co-Authors: Anastasiya V. Agafonova, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Galina L. Starova, Ilia A. Smetanin, Mikhail S. NovikovAbstract:An effective and operationally simple method for the preparation of methyl 2-(di/tri/tetraazol-1-yl)-2H-Azirine-2-carboxylates from accessible methyl 2-halo-2H-Azirine-2-carboxylates and NH-azoles has been developed. The azoles having enhanced NH acidity, react with 2-halo-2H-Azirines in the presence of Et3N in a deprotonated form, while the azoles having highly nucleophilic sp2 nitrogen react in neutral form. According to the DFT calculations, the substitution of the halogen by the azole proceeds via an SN2′-SN2′ cascade, with the initial conjugate substitution of the halogen being the rate-determining step. The formation of 2,3-dipyrazolylaziridines in the reaction of pyrazole provides experimental evidence for the cascade mechanism of the reaction
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Synthesis of 1,2-Dihydropyrimidine-2-carboxylates via Regioselective Addition of Rhodium(II) Carbenoids to 2H‑Azirine-2-carbaldimines
2017Co-Authors: Mikhail S. Novikov, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Kirill V. Zavyalov, Alexander N Koronatov, Grigory V. Zubakin, Galina L. StarovaAbstract:An efficient two-step procedure “imine formation/azirine–carbenoid coupling” has been developed for the preparation of 1,2-dihydropyrimidines from azirine-2-carbaldehydes, primary amines, and diazo carbonyl compounds under Rh(II) catalysis. The formation of 1,2-dihydropyrimidines involves 100% regioselective addition of the rhodium carbenoid to endocyclic nitrogen atom of the 2H-Azirine-2-carbaldimine. According to the DFT calculations the reaction proceeds via dissociation of the metal-bound complex of the azirinium ylide to metal-free azirinium ylide, ring-opening of the latter to give a 1,5-diazahexa-1,3,5-triene, followed by 1,6-cyclization. The 1,2-dihydropyrimidines with two different electron-withdrawing substituents at the C2 position can undergo in solution inversion of configuration of the stereogenic center at C2 via “the N1–C2 bond cleavage/rotation around the N–C single bond/1,6-cyclization” sequence
Nikolai V. Rostovskii - One of the best experts on this subject based on the ideXlab platform.
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regiodivergent synthesis of butenolide based α and β amino acid derivatives via base controlled azirine ring expansion
Organic Letters, 2020Co-Authors: Pavel A Sakharov, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Mikhail S. NovikovAbstract:A method for the preparation of 5-aminobutenolides from 2-bromo-2H-Azirine-2-carboxylic esters/amides with arylacetic acids has been developed. The reaction regioselectivity can be switched by a change of the basic catalyst, making it possible to prepare both butenolide-based α- and β-amino acid derivatives. The change in the regioselectivity is interpreted in terms of the stability and reactivity of the enolates formed during the SN2' substitution of the bromine in the azirine by the carboxylate ion.
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Advances in 2H-Azirine chemistry: A seven-year update
Tetrahedron, 2019Co-Authors: Alexander F. Khlebnikov, Mikhail S. Novikov, Nikolai V. RostovskiiAbstract:Abstract 2H-Azirines are versatile building blocks for the preparation of various nitrogen-containing heterocycles. Seven years ago the comprehensive review on azirine chemistry was published in Tetrahedron. Since then, there had been an explosion of research activities in the field of these strained molecules. This renaissance is primarily associated with the discovery of new reactivity of azirines and in particular new catalytic and light-induced reactions, which made possible unusual transformations of this three-membered N-heterocycle into azole and azine derivatives as well as polyheterocyclic systems. The second reason for the progress of azirine chemistry is the development of methods for the preparation of new azirine derivatives. The third reason is the discovery of new synthetic equivalents of azirines, which permitted avoiding the use of unstable azirines in some modern catalytic procedures. In the present comprehensive review, we have placed particular emphasis on discussing the new developments in the synthesis and reactivity of azirines for the period from 2012 until the end of 2018.
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2H‑Azirines as C–C Annulation Reagents in Cu-Catalyzed Synthesis of Furo[3,2‑c]quinolone Derivatives
2019Co-Authors: Pavel A. Sakharov, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Taras L. Panikorovskii, Mikhail S. NovikovAbstract:A method of furo-annulation of 4-hydroxy-2-oxoquinoline-3-carboxylates with 3-arylazirines under Cu(II) catalysis was developed to synthesize a variety of 2,3-dihydrofuro[3,2-c]quinolones bearing a carbamate group at the C2 position. The reaction involves an azirine ring opening across the N–C2 bond and formation of a dihydrofuran ring with the inclusion of two azirine carbon atoms, accompanied by a shift of the ester group to the nitrogen. The discovered reaction is the first example of the use of 2H-Azirines for furo-annulation
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synthesis of 2 di tri tetraazolyl 2h azirine 2 carboxylates by halogen substitution evidence for an sn2 sn2 cascade mechanism
Journal of Organic Chemistry, 2018Co-Authors: Anastasiya V. Agafonova, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Galina L. Starova, Ilia A. Smetanin, Mikhail S. NovikovAbstract:An effective and operationally simple method for the preparation of methyl 2-(di/tri/tetraazol-1-yl)-2H-Azirine-2-carboxylates from accessible methyl 2-halo-2H-Azirine-2-carboxylates and NH-azoles has been developed. The azoles having enhanced NH acidity, react with 2-halo-2H-Azirines in the presence of Et3N in a deprotonated form, while the azoles having highly nucleophilic sp2 nitrogen react in neutral form. According to the DFT calculations, the substitution of the halogen by the azole proceeds via an SN2′-SN2′ cascade, with the initial conjugate substitution of the halogen being the rate-determining step. The formation of 2,3-dipyrazolylaziridines in the reaction of pyrazole provides experimental evidence for the cascade mechanism of the reaction.
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Synthesis of 2‑(Di/tri/tetraazolyl)‑2H‑azirine-2-carboxylates by Halogen Substitution: Evidence for an SN2′‑SN2′ Cascade Mechanism
2018Co-Authors: Anastasiya V. Agafonova, Nikolai V. Rostovskii, Alexander F. Khlebnikov, Galina L. Starova, Ilia A. Smetanin, Mikhail S. NovikovAbstract:An effective and operationally simple method for the preparation of methyl 2-(di/tri/tetraazol-1-yl)-2H-Azirine-2-carboxylates from accessible methyl 2-halo-2H-Azirine-2-carboxylates and NH-azoles has been developed. The azoles having enhanced NH acidity, react with 2-halo-2H-Azirines in the presence of Et3N in a deprotonated form, while the azoles having highly nucleophilic sp2 nitrogen react in neutral form. According to the DFT calculations, the substitution of the halogen by the azole proceeds via an SN2′-SN2′ cascade, with the initial conjugate substitution of the halogen being the rate-determining step. The formation of 2,3-dipyrazolylaziridines in the reaction of pyrazole provides experimental evidence for the cascade mechanism of the reaction
Jian Wang - One of the best experts on this subject based on the ideXlab platform.
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carbene catalyzed 4 2 annulation of 2 h azirine 2 carboxaldehydes with ketones via azolium aza dienolate intermediate
Organic Letters, 2018Co-Authors: Qiupeng Peng, Bei Zhang, Yangxi Xie, Jian WangAbstract:A new carbene-catalyzed [4 + 2] annulation of 2H-Azirine-2-carbaldehydes with ketones was developed, thus providing the 2,3-dihydro-6H-1,3-oxazin-6-one core structures with broad scope and good to excellent yields. Notably, the azolium aza-dienolates generated from the addition of NHCs to 2H-Azirines are first uncovered.
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Carbene-Catalyzed [4 + 2] Annulation of 2H‑Azirine-2-carboxaldehydes with Ketones via Azolium Aza-Dienolate Intermediate
2018Co-Authors: Qiupeng Peng, Bei Zhang, Yangxi Xie, Jian WangAbstract:A new carbene-catalyzed [4 + 2] annulation of 2H-Azirine-2-carbaldehydes with ketones was developed, thus providing the 2,3-dihydro-6H-1,3-oxazin-6-one core structures with broad scope and good to excellent yields. Notably, the azolium aza-dienolates generated from the addition of NHCs to 2H-Azirines are first uncovered
