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Yoann Coquerel - One of the best experts on this subject based on the ideXlab platform.
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Experimental and theoretical studies of (4 + 1) annulations between α‐oxoketenes and stable phosphorous, nitrogen, or sulfur ylides
2019Co-Authors: David Pierrot, Michel Rajzmann, Jean Rodriguez, Yannick Carissan, Damien Bonne, Yoann CoquerelAbstract:α‐Oxoketenes generated in situ by a microwave‐assisted Wolff Rearrangement at 170°C were found to react with stabilized sulfur ylides in (4 + 1) annulation processes to afford functionalized 3‐hydroxyfurans. Theoretical mechanistic investigations revealed that the reaction proceeds in two steps via a short‐lived betaine intermediate, a general feature of the reactions of α‐oxoketenes with stable phosphorous, nitrogen, and sulfur ylides.
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Time-Efficient Synthesis of Pyrido[2,3-d]pyrimidinones via α-Oxoketenes
2016Co-Authors: Juan-carlos Castillo, Jairo Quiroga, Jean Rodriguez, Yoann CoquerelAbstract:α-Oxoketene reactive intermediates generated in situ by microwave-assisted Wolff Rearrangement of 2-diazo-1,3- dicarbonyl compounds have been found to react with 6-aminopyrimidine derivatives as 1,3-C,N-bis-nucleophiles to yield pyrido[2,3-d]pyrimidinones and related compounds amenable to further functionalization.
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divergent chemo regio and diastereoselective normal electron demand povarov type reactions with α oxo ketene dienophiles
ChemInform, 2015Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reaction between electron-rich 2-aza-dienes (I), (IV), (VI), and (IX) and α-oxo-ketenes, derived from the Wolff Rearrangement of 2-diazocycloalkane-diones such as (II) affords spiro hydropyridones (III) and (V) with good to excellent diastereoselectivity.
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divergent chemo regio and diastereoselective normal electron demand povarov type reactions with α oxo ketene dienophiles
Organic Letters, 2014Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff Rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel–Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles.
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Divergent Chemo‑, Regio‑, and Diastereoselective Normal Electron-Demand Povarov-Type Reactions with α‑Oxo-ketene Dienophiles
2014Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff Rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel–Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles
Jean Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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Experimental and theoretical studies of (4 + 1) annulations between α‐oxoketenes and stable phosphorous, nitrogen, or sulfur ylides
2019Co-Authors: David Pierrot, Michel Rajzmann, Jean Rodriguez, Yannick Carissan, Damien Bonne, Yoann CoquerelAbstract:α‐Oxoketenes generated in situ by a microwave‐assisted Wolff Rearrangement at 170°C were found to react with stabilized sulfur ylides in (4 + 1) annulation processes to afford functionalized 3‐hydroxyfurans. Theoretical mechanistic investigations revealed that the reaction proceeds in two steps via a short‐lived betaine intermediate, a general feature of the reactions of α‐oxoketenes with stable phosphorous, nitrogen, and sulfur ylides.
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Time-Efficient Synthesis of Pyrido[2,3-d]pyrimidinones via α-Oxoketenes
2016Co-Authors: Juan-carlos Castillo, Jairo Quiroga, Jean Rodriguez, Yoann CoquerelAbstract:α-Oxoketene reactive intermediates generated in situ by microwave-assisted Wolff Rearrangement of 2-diazo-1,3- dicarbonyl compounds have been found to react with 6-aminopyrimidine derivatives as 1,3-C,N-bis-nucleophiles to yield pyrido[2,3-d]pyrimidinones and related compounds amenable to further functionalization.
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divergent chemo regio and diastereoselective normal electron demand povarov type reactions with α oxo ketene dienophiles
ChemInform, 2015Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reaction between electron-rich 2-aza-dienes (I), (IV), (VI), and (IX) and α-oxo-ketenes, derived from the Wolff Rearrangement of 2-diazocycloalkane-diones such as (II) affords spiro hydropyridones (III) and (V) with good to excellent diastereoselectivity.
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divergent chemo regio and diastereoselective normal electron demand povarov type reactions with α oxo ketene dienophiles
Organic Letters, 2014Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff Rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel–Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles.
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Divergent Chemo‑, Regio‑, and Diastereoselective Normal Electron-Demand Povarov-Type Reactions with α‑Oxo-ketene Dienophiles
2014Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff Rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel–Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles
Curt Wentrup - One of the best experts on this subject based on the ideXlab platform.
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Iminocyclohexadienylidenes: Carbenes or Diradicals? The Hetero-Wolff Rearrangement of Benzotriazoles to Cyanocyclopentadienes and 1H‑Benzo[b]azirines
2017Co-Authors: Didier Bégué, Alain Dargelos, Hugo Santos-silva, Curt WentrupAbstract:The thermal Rearrangements of benzotriazole 1 to fulvenimine 4 and 1H-benzazirine 7 are investigated at DFT and CASPT2 levels of theory. Ring opening of benzotriazole 1 to 2-diazo-cyclohexadienimine 2 followed by N2 elimination affords Z- and E-2-iminocyclohexadienylidenes 3, which have triplet ground states (3A″). The open-shell singlet (OSS) (1A″) and closed-shell singlet (CSS) (1A′) of 3 lie ∼15 and 40 kcal/mol higher in free energy, respectively. The OSS 3 (1A″) is best described as a 1,3-diradical, whereas the CSS (1A′) has the character of a carbene. A hetero-Wolff Rearrangement of OSS 3 yields fulvenimine 4, which is a precursor of cyanocyclopentadiene 5, with a calculated activation barrier of 38 kcal/mol at the CASPT2(8,8) level, whereby there is a surface crossing from the OSS to the CSS near the transition state. The barrier for cyclization to 1H-benzo[b]azirine 7 is only ∼13 kcal/mol. Therefore, reaction paths involving the singlet iminocyclohexadienylidene diradicals 3 will necessarily cause equilibration with 1H-benzazirine 7 prior to ring contraction to iminofulvene 4 and cyanocyclopentadiene 5, in agreement with experimental observations based on 13C labeling. The thermolysis of 1-acetylbenzotriazole 7 leads to the analogous N-acetyl-diazocyclohexadienimines 8, N-acetyliminocyclohexadienylidene diradicals 9, and N-acetylfulvenimine 10. The E-N-acetyliminocyclohexadienylidene E9 ring closes to the N-acetyl-1H-benzazirine 11 prior to ring contraction to N-acetylfulvenimine 10, and the Z-N-acetyl-2-diazocyclohexadienimine Z8 ring closes to 2-methylbenzoxazole 12. 1H-benzazirines are predicted to be spectroscopically observable species
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Iminocyclohexadienylidenes: Carbenes or Diradicals? the Hetero-Wolff Rearrangement of Benzotriazoles to Cyanocyclopentadienes and 1H-Benzo[b]azirines
Journal of Physical Chemistry A, 2017Co-Authors: D. Bégué, Alain Dargelos, Hugo Santos-silva, Curt WentrupAbstract:The thermal Rearrangements of benzotriazole 1 to fulvenimine 4 and 1H-benzazirine 7 are investigated at DFT and CASPT2 levels of theory. Ring opening of benzotriazole 1 to 2-diazo-cyclohexadienimine 2 followed by N2 elimination affords Z- and E-2-iminocyclohexadienylidenes 3, which have triplet ground states (3A″). The open-shell singlet (OSS) (1A″) and closed-shell singlet (CSS) (1A′) of 3 lie ∼15 and 40 kcal/mol higher in free energy, respectively. The OSS 3 (1A″) is best described as a 1,3-diradical, whereas the CSS (1A′) has the character of a carbene. A hetero-Wolff Rearrangement of OSS 3 yields fulvenimine 4, which is a precursor of cyanocyclopentadiene 5, with a calculated activation barrier of 38 kcal/mol at the CASPT2(8,8) level, whereby there is a surface crossing from the OSS to the CSS near the transition state. The barrier for cyclization to 1H-benzo[b]azirine 7 is only ∼13 kcal/mol. Therefore, reaction paths involving the singlet iminocyclohexadienylidene diradicals 3 will necessarily cause equilibration with 1H-benzazirine 7 prior to ring contraction to iminofulvene 4 and cyanocyclopentadiene 5, in agreement with experimental observations based on 13C labeling. The thermolysis of 1-acetylbenzotriazole 7 leads to the analogous N-acetyl-diazocyclohexadienimines 8, N-acetyliminocyclohexadienylidene diradicals 9, and N-acetylfulvenimine 10. The E-N-acetyliminocyclohexadienylidene E9 ring closes to the N-acetyl-1H-benzazirine 11 prior to ring contraction to N-acetylfulvenimine 10, and the Z-N-acetyl-2-diazocyclohexadienimine Z8 ring closes to 2-methylbenzoxazole 12. 1H-benzazirines are predicted to be spectroscopically observable species.
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Ketene–Ketene Interconversion. 6‑Carbonylcyclohexa-2,4-dienone–Hepta-1,2,4,6-tetraene-1,7-dione–6-Oxocyclohexa-2,4-dienylidene and Wolff Rearrangement to Fulven-6-one
2014Co-Authors: Rainer Koch, Rodney J. Blanch, Curt WentrupAbstract:6-Carbonylcyclohexa-2,4-dienone (1) has been generated by flash vacuum thermolysis (FVT) with Ar-matrix isolation of methyl salicylate (7), 2-phenylbenzo-1,3-dioxan-4-one (8), phthalic peranhydride (9), and benzofuran-2,3-dione (11) and also by matrix photolysis of 9, 11, and 2-diazocyclohepta-4,6-dien-1,3-dione (12). In each case, FVT above 600 °C results in decarbonylation of 1 and Wolff Rearrangement to fulven-6-one (13) either concertedly or via open-shell singlet 6-oxocyclohexa-2,4-dienylidene (18). Ketenes 1 and 13 were characterized by IR spectroscopy. Photolysis of matrix-isolated 1 at 254 nm also results in the slow formation of 13. The sequential formation of ketenes 1 and 13 from 7 has also been monitored by FVT-mass spectrometry, and 13 has been trapped with MeOH to afford methyl 1,3-cyclopentadiene-1- and -2-carboxylates 15 and 16. FVT of methyl salicylate-1-13C 7a revealed a deep-seated Rearrangement of the 13C-labeled 1a to hepta-1,2,4,6-tetraen-1,7-dione (17a) by means of electrocyclic ring opening followed by a facile 1,5-H shift and recyclization prior to CO-elimination and ring contraction to 13C-labeled 13. The Rearrangement mechanism is supported by M06-2X/6-311++G(d,p) calculations, which predict feasible barriers for the FVT Rearrangements and confirm the observed labeling pattern in the isolated methyl salicylate 7a/7b and methyl cyclopentadienecarboxylates 20 and 21 resulting from trapping of 13 with MeOH
Juan-carlos Castillo - One of the best experts on this subject based on the ideXlab platform.
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Time-Efficient Synthesis of Pyrido[2,3-d]pyrimidinones via α-Oxoketenes
2016Co-Authors: Juan-carlos Castillo, Jairo Quiroga, Jean Rodriguez, Yoann CoquerelAbstract:α-Oxoketene reactive intermediates generated in situ by microwave-assisted Wolff Rearrangement of 2-diazo-1,3- dicarbonyl compounds have been found to react with 6-aminopyrimidine derivatives as 1,3-C,N-bis-nucleophiles to yield pyrido[2,3-d]pyrimidinones and related compounds amenable to further functionalization.
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divergent chemo regio and diastereoselective normal electron demand povarov type reactions with α oxo ketene dienophiles
ChemInform, 2015Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reaction between electron-rich 2-aza-dienes (I), (IV), (VI), and (IX) and α-oxo-ketenes, derived from the Wolff Rearrangement of 2-diazocycloalkane-diones such as (II) affords spiro hydropyridones (III) and (V) with good to excellent diastereoselectivity.
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divergent chemo regio and diastereoselective normal electron demand povarov type reactions with α oxo ketene dienophiles
Organic Letters, 2014Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff Rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel–Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles.
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Divergent Chemo‑, Regio‑, and Diastereoselective Normal Electron-Demand Povarov-Type Reactions with α‑Oxo-ketene Dienophiles
2014Co-Authors: Jaime Gálvez, Jairo Quiroga, Juan-carlos Castillo, Michel Rajzmann, Jean Rodriguez, Yoann CoquerelAbstract:The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff Rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel–Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles
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microwave assisted domino benzannulation of α oxo ketenes preparation of 1 3 dihydro 2h 1 5 benzodiazepin 2 ones
ChemInform, 2012Co-Authors: Juan-carlos Castillo, Yoann Coquerel, Marc Presset, Rodrigo Abonia, Jean RodriguezAbstract:The title reaction of 2-diazo-1,3-diones and o-phenylenediamines in the absence of any additive affords bi- or tricyclic benzodiazepinones by a domino Wolff Rearrangement/nucleophilic addition/intramolecular imination sequence with the formation of three new covalent bonds.
Yong Rok Lee - One of the best experts on this subject based on the ideXlab platform.
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synthesis of diverse isatins via ring contraction of 3 diazoquinoline 2 4 diones
ChemInform, 2016Co-Authors: Rajeev Shrestha, Gun Joon Lee, Yong Rok LeeAbstract:The reaction proceeds via domino Wolff Rearrangement, decarboxylation, bromination, substitution, and dehydration.
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synthesis of diverse isatins via ring contraction of 3 diazoquinoline 2 4 diones
RSC Advances, 2016Co-Authors: Rajeev Shrestha, Gun Joon Lee, Yong Rok LeeAbstract:An efficient synthesis of diverse isatin derivatives was accomplished by a copper-mediated reaction of 3-diazoquinoline-2,4-diones via ring contraction through domino Wolff Rearrangement, decarboxylation, bromination, substitution, and dehydration. This protocol has several advantages as a one-pot procedure, with functional group tolerance, and high yield.
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synthesis of diverse indene derivatives from 1 diazonaphthalen 2 1h ones via thermal cascade reactions
ChemInform, 2014Co-Authors: Krishna Bahadur Somai Magar, Yong Rok LeeAbstract:A sequential Wolff Rearrangement of 1-diazonaphthalen-2(1H)-ones (I) followed by trapping of the ketene intermediate with primary and aromatic amines or alcohols and phenols in the presence of various aldehydes generates 1H-indene-3-carboxamides or 1H-indene-3-carboxylates.
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synthesis of diverse indene derivatives from 1 diazonaphthalen 2 1h ones via thermal cascade reactions
Organic Letters, 2013Co-Authors: Krishna Bahadur Somai Magar, Yong Rok LeeAbstract:A sequential Wolff Rearrangement of 1-diazonaphthalen-2(1H)-ones followed by trapping of the ketene intermediate with primary and aromatic amines or alcohols and phenols in the presence of various aldehydes generates 1H-indene-3-carboxamides or 1H-indene-3-carboxylates. This constitutes an unprecedented three-component coupling reaction that allows for the synthesis of functionalized indene derivatives under catalyst-free thermal conditions.
