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Meixiang Wang - One of the best experts on this subject based on the ideXlab platform.
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catalytic asymmetric tandem reaction of tertiary Enamides expeditious synthesis of pyrrolo 2 1 a isoquinoline alkaloid derivatives
Angewandte Chemie, 2016Co-Authors: Liang Zhao, Jieping Zhu, Meixiang WangAbstract:Reported is a new and efficient strategy for rapid construction of the chiral tetrahydropyrrolo[2,1-a]isoquinolin-3(2H)-one structure from unique tertiary Enamide synthons. A Cu(OTf)2 /chiral Pybox complex catalyzes the intramolecular enantioselective addition of tertiary Enamides to ketonic carbonyls with subsequent diastereoselective interception of the resulting acyliminium by tethered electron-rich aryl moiety. The tandem reaction produces diverse tetrahydropyrrolo[2,1-a]isoquinolin-3(2H)-one derivatives as the sole diastereoisomers in good to excellent yields with up to 98.5 % ee. The transformations of the resulting heterocycles into various hexahydropyrrolo[2,1-a]isoquinoline derivatives were also demonstrated. The cyclization products, which are difficult to obtain by other synthetic means, are structural motifs found in many bioactive alkaloids.
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synthesis of 2 3 dihydro 1h azepine and 1h azepin 2 3h one derivatives from intramolecular condensation between stable tertiary Enamides and aldehydes
Journal of Organic Chemistry, 2015Co-Authors: Wenju Zhu, Liang Zhao, Meixiang WangAbstract:A new strategy to construct 2,3-dihydro-1H-azepine and 1H-azepin-2(3H)-one heterocyclic rings is reported based on emerging tertiary Enamide synthons. Under very mild conditions employing BBr3 as a Lewis acid catalyst and P2O5 as an additive, tertiary Enamides that contain a formyl group underwent highly efficient and scalable intramolecular cyclic condensation to afford diverse 2,3-dihydro-1H-azepine and 1H-azepin-2(3H)-one derivatives in 71–96% yields. The reaction proceeded most probably through a nucleophilic addition of Enamides to aldehyde, deprotonation, and dehydration cascade. Application of the method in the synthesis of dihydro-azepino[2,1-a]isoindol-5-ones, the core structure of naturally occurring lennoxamine, was also demonstrated.
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synthesis of diverse di to penta substituted 1 2 dihydropyridine derivatives from gold i catalyzed intramolecular addition of tertiary Enamides to alkynes
Tetrahedron Letters, 2015Co-Authors: Xingyi Zhang, Liang Zhao, Jieping Zhu, Jingsong You, Meixiang WangAbstract:As 3-aza-1,5-enynes, internal and terminal alkyne-bearing tertiary Enamides underwent an efficient Au(I)-catalyzed 6-endo-dig cyclization reaction to afford a variety of di- to penta-substituted 1,2-dihydropyridine derivatives in high yields. The cyclization proceeds through a cascade comprising an intramolecular nucleophilic addition of enaminic carbon to alkyne–gold(I) complex, deprotonation, and protodeauration steps. Au(I)-catalyzed tertiary Enamide–alkyne cyclization coupled with consecutive oxidative aromatization provided a straightforward route to polysubstituted pyridines.
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synthesis of substituted pyridines from cascade 1 5 cycloaddition of isonitriles to n formylmethyl substituted Enamides aerobic oxidative aromatization and acyl transfer reaction
Journal of the American Chemical Society, 2013Co-Authors: Chuanhu Lei, Liang Zhao, Jieping Zhu, Dexian Wang, Meixiang WangAbstract:A novel strategy for de novo synthesis of pyridines featuring an unprecedented α-addition of aldehyde and Enamide to isonitrile as a key step is described. Under mild conditions, a cascade reaction involving Zn(OTf)2-promoted [1 + 5] cycloaddition of isonitrile with N-formylmethyl-substituted Enamide, facile aerobic oxidative aromatization and intermolecular acyl transfer from the pyridinium nitrogen to the 5-hydroxy oxygen, and finally acylation of the 4-amino group by an external acyl chloride efficiently afforded 2-substituted 4-acylamino-5-acyloxypyridines in good to excellent yields.
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synthesis of 4 amino 1 2 3 4 tetrahydropyridine derivatives by intramolecular nucleophilic addition of tertiary Enamides to in situ generated imines
Tetrahedron, 2012Co-Authors: Shuo Tong, Liang Zhao, Jieping Zhu, Meixiang Wang, Xu Yang, Dexian WangAbstract:The reactivity of stable tertiary Enamides in nucleophilic addition reaction with various in-situ generated imines was explored. Under very mild conditions, formyl-bearing tertiary Enamides reacted with both aromatic and aliphatic amines to form imine intermediates. In the absence or presence of p-toluenesulfonic acid as a catalyst, intramolecular nucleophilic addition of Enamide to imine functionality proceeded effectively to produce diverse 4-amino-1,2,3,4-tetrahydropyridine derivatives in good to excellent yields.
Rodolfo Marquez - One of the best experts on this subject based on the ideXlab platform.
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structure activity analysis of cj 15 801 analogues that interact with plasmodium falciparum pantothenate kinase and inhibit parasite proliferation
European Journal of Medicinal Chemistry, 2018Co-Authors: Christina Spry, Alan L Sewell, Yuliya Hering, Mathew V J Villa, Jonas Weber, Stephen J Hobson, Suzannah J Harnor, Sheraz Gul, Rodolfo MarquezAbstract:Abstract Survival of the human malaria parasite Plasmodium falciparum is dependent on pantothenate (vitamin B5), a precursor of the fundamental enzyme cofactor coenzyme A. CJ-15,801, an Enamide analogue of pantothenate isolated from the fungus Seimatosporium sp. CL28611, was previously shown to inhibit P. falciparum proliferation in vitro by targeting pantothenate utilization. To inform the design of next generation analogues, we set out to synthesize and test a series of synthetic Enamide-bearing pantothenate analogues. We demonstrate that conservation of the R-pantoyl moiety and the trans-substituted double bond of CJ-15,801 is important for the selective, on-target antiplasmodial effect, while replacement of the carboxyl group is permitted, and, in one case, favored. Additionally, we show that the antiplasmodial potency of CJ-15,801 analogues that retain the R-pantoyl and trans-substituted Enamide moieties correlates with inhibition of P. falciparum pantothenate kinase (PfPanK)-catalyzed pantothenate phosphorylation, implicating the interaction with PfPanK as a key determinant of antiplasmodial activity.
Liang Zhao - One of the best experts on this subject based on the ideXlab platform.
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catalytic asymmetric tandem reaction of tertiary Enamides expeditious synthesis of pyrrolo 2 1 a isoquinoline alkaloid derivatives
Angewandte Chemie, 2016Co-Authors: Liang Zhao, Jieping Zhu, Meixiang WangAbstract:Reported is a new and efficient strategy for rapid construction of the chiral tetrahydropyrrolo[2,1-a]isoquinolin-3(2H)-one structure from unique tertiary Enamide synthons. A Cu(OTf)2 /chiral Pybox complex catalyzes the intramolecular enantioselective addition of tertiary Enamides to ketonic carbonyls with subsequent diastereoselective interception of the resulting acyliminium by tethered electron-rich aryl moiety. The tandem reaction produces diverse tetrahydropyrrolo[2,1-a]isoquinolin-3(2H)-one derivatives as the sole diastereoisomers in good to excellent yields with up to 98.5 % ee. The transformations of the resulting heterocycles into various hexahydropyrrolo[2,1-a]isoquinoline derivatives were also demonstrated. The cyclization products, which are difficult to obtain by other synthetic means, are structural motifs found in many bioactive alkaloids.
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synthesis of 2 3 dihydro 1h azepine and 1h azepin 2 3h one derivatives from intramolecular condensation between stable tertiary Enamides and aldehydes
Journal of Organic Chemistry, 2015Co-Authors: Wenju Zhu, Liang Zhao, Meixiang WangAbstract:A new strategy to construct 2,3-dihydro-1H-azepine and 1H-azepin-2(3H)-one heterocyclic rings is reported based on emerging tertiary Enamide synthons. Under very mild conditions employing BBr3 as a Lewis acid catalyst and P2O5 as an additive, tertiary Enamides that contain a formyl group underwent highly efficient and scalable intramolecular cyclic condensation to afford diverse 2,3-dihydro-1H-azepine and 1H-azepin-2(3H)-one derivatives in 71–96% yields. The reaction proceeded most probably through a nucleophilic addition of Enamides to aldehyde, deprotonation, and dehydration cascade. Application of the method in the synthesis of dihydro-azepino[2,1-a]isoindol-5-ones, the core structure of naturally occurring lennoxamine, was also demonstrated.
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synthesis of diverse di to penta substituted 1 2 dihydropyridine derivatives from gold i catalyzed intramolecular addition of tertiary Enamides to alkynes
Tetrahedron Letters, 2015Co-Authors: Xingyi Zhang, Liang Zhao, Jieping Zhu, Jingsong You, Meixiang WangAbstract:As 3-aza-1,5-enynes, internal and terminal alkyne-bearing tertiary Enamides underwent an efficient Au(I)-catalyzed 6-endo-dig cyclization reaction to afford a variety of di- to penta-substituted 1,2-dihydropyridine derivatives in high yields. The cyclization proceeds through a cascade comprising an intramolecular nucleophilic addition of enaminic carbon to alkyne–gold(I) complex, deprotonation, and protodeauration steps. Au(I)-catalyzed tertiary Enamide–alkyne cyclization coupled with consecutive oxidative aromatization provided a straightforward route to polysubstituted pyridines.
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synthesis of substituted pyridines from cascade 1 5 cycloaddition of isonitriles to n formylmethyl substituted Enamides aerobic oxidative aromatization and acyl transfer reaction
Journal of the American Chemical Society, 2013Co-Authors: Chuanhu Lei, Liang Zhao, Jieping Zhu, Dexian Wang, Meixiang WangAbstract:A novel strategy for de novo synthesis of pyridines featuring an unprecedented α-addition of aldehyde and Enamide to isonitrile as a key step is described. Under mild conditions, a cascade reaction involving Zn(OTf)2-promoted [1 + 5] cycloaddition of isonitrile with N-formylmethyl-substituted Enamide, facile aerobic oxidative aromatization and intermolecular acyl transfer from the pyridinium nitrogen to the 5-hydroxy oxygen, and finally acylation of the 4-amino group by an external acyl chloride efficiently afforded 2-substituted 4-acylamino-5-acyloxypyridines in good to excellent yields.
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synthesis of 4 amino 1 2 3 4 tetrahydropyridine derivatives by intramolecular nucleophilic addition of tertiary Enamides to in situ generated imines
Tetrahedron, 2012Co-Authors: Shuo Tong, Liang Zhao, Jieping Zhu, Meixiang Wang, Xu Yang, Dexian WangAbstract:The reactivity of stable tertiary Enamides in nucleophilic addition reaction with various in-situ generated imines was explored. Under very mild conditions, formyl-bearing tertiary Enamides reacted with both aromatic and aliphatic amines to form imine intermediates. In the absence or presence of p-toluenesulfonic acid as a catalyst, intramolecular nucleophilic addition of Enamide to imine functionality proceeded effectively to produce diverse 4-amino-1,2,3,4-tetrahydropyridine derivatives in good to excellent yields.
Laurence Miesch - One of the best experts on this subject based on the ideXlab platform.
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tertiary Enamide triggered sear domino allylation and enamine type addition
Organic Letters, 2019Co-Authors: Frederic Beltran, Laurence MieschAbstract:Two unprecedented domino reactions are described, starting from ketospiro-enesulfonamides. By treatment with ZrCl4 and allylsilane, an intramolecular electrophilic aromatic substitution and subsequent allylation is observed. By treatment with TiCl4 and allylsilane, a double enamine-type reaction takes place, thus creating simultaneously four contiguous stereogenic centers diastereoselectively.
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Tertiary Enamide-Triggered SEAr: Domino Allylation and Enamine-Type Addition
2019Co-Authors: Frédéric Beltran, Laurence MieschAbstract:Two unprecedented domino reactions are described, starting from ketospiro-enesulfonamides. By treatment with ZrCl4 and allylsilane, an intramolecular electrophilic aromatic substitution and subsequent allylation is observed. By treatment with TiCl4 and allylsilane, a double enamine-type reaction takes place, thus creating simultaneously four contiguous stereogenic centers diastereoselectively
John A Porco - One of the best experts on this subject based on the ideXlab platform.
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synthesis and cell cycle inhibition of the peptide Enamide natural products terpeptin and the aspergillamides
Tetrahedron, 2003Co-Authors: Hideaki Kakeya, Hiroyuki Osada, John A PorcoAbstract:Abstract Total syntheses of the peptide Enamide natural products terpeptin and aspergillamides A and B are reported. An oxidative decarboxylation–elimination protocol is employed to construct the indolic Enamide moiety. Unambiguous stereochemical assignment of (−)-terpeptin is accomplished by synthesis of all possible stereochemical analogues. Select compounds have been evaluated in cell cycle inhibitor assays which show that the natural amino acid configuration of terpeptin has the most potent inhibitory activity.
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total synthesis of the salicylate Enamide macrolide oximidine ii
Journal of the American Chemical Society, 2003Co-Authors: Xiang Wang, John A PorcoAbstract:The asymmetric synthesis of the salicylate Enamide macrolide oximidine II is reported. The synthesis involves a highly regio- and stereoselective ring-closing metathesis of a bis-diene substrate to construct the macrocyclic triene core. Copper(I)-mediated amidation of a (Z)-vinyl iodide was employed to attach the Enamide side chain.
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synthesis of Enamides related to the salicylate antitumor macrolides using copper mediated vinylic substitution
Organic Letters, 2000Co-Authors: Ruichao Shen, John A PorcoAbstract:A new approach to the assembly of Enamides is described using copper(I) carboxylate-catalyzed substitution of vinyl iodides and amides. Modified reaction conditions have been developed to synthesize the O-methyloxime Enamide side chains related to the natural products lobatamides A−F, oximidine I and II, and CJ-12 950.