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A V Stepakov - One of the best experts on this subject based on the ideXlab platform.
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Stereo- and Regioselective 1,3-Dipolar Cycloaddition of the Stable Ninhydrin-Derived Azomethine Ylide to Cyclopropenes: Trapping of Unstable Cyclopropene Dipolarophiles
2019Co-Authors: Alexander S. Filatov, Anna G Larina, Vitali M Boitsov, Siqi Wang, Olesya V. Khoroshilova, Stanislav V. Lozovskiy, A V StepakovAbstract:A stereo- and regioselective 1,3-dipolar cycloaddition of the stable ninhydrin-derived azomethine ylide [2-(3,4-dihydro-2H-pyrrolium-1-yl)-1-oxo-1H-inden-3-olate, DHPO] to differently substituted Cyclopropenes has been established. As a result, an efficient synthetic protocol was developed for the preparation of biologically relevant spiro[cyclopropa[a]pyrrolizine-2,2′-indene] derivatives. DHPO has proved to be an effective trap for such highly reactive and unstable substrates as parent cyclopropene, 1-methylcyclopropene, 1-phenylcyclopropene, and 1-halo-2-phenylCyclopropenes. It has also been found that 3-nitro-1,2-diphenylcyclopropene undergoes a nucleophilic substitution reaction in alcohols and thiols to afford 3-alkoxy- and 3-arylthio-substituted 1,2-diphenylCyclopropenes, which can be captured as corresponding 1,3-dipolar cycloadducts in the presence of DHPO. These new approaches provide a straightforward strategy for the synthesis of functionally substituted cyclopropa[a]pyrrolizine derivatives. The factors governing regio- and stereoselectivity have been revealed by means of quantum mechanical calculations (M11 density functional theory), including previously unreported Nylide–Hcyclopropene second-orbital interactions. The outcome of this work contributes to the study of 1,3-dipolar cycloaddition, as well as enriches chemistry of Cyclopropenes and methods for the construction of polycyclic compounds with cyclopropane fragments
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synthesis of functionalized 3 spiro cyclopropa a pyrrolizine and 3 spiro 3 azabicyclo 3 1 0 hexane oxindoles from Cyclopropenes and azomethine ylides via 3 2 cycloaddition
Journal of Organic Chemistry, 2017Co-Authors: Alexander S Filatov, Nickolay A Knyazev, A P Molchanov, Taras L Panikorovsky, R R Kostikov, Anna G Larina, Vitali M Boitsov, A V StepakovAbstract:3-Spiro[cyclopropa[a]pyrrolizine]- and 3-spiro[3-azabicyclo[3.1.0]hexane]oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and Cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro.
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Synthesis of Functionalized 3‑Spiro[cyclopropa[a]pyrrolizine]- and 3‑Spiro[3-azabicyclo[3.1.0]hexane]oxindoles from Cyclopropenes and Azomethine Ylides via [3 + 2]-Cycloaddition
2016Co-Authors: Alexander S. Filatov, Rafael R. Kostikov, Alexander P. Molchanov, Nickolay A Knyazev, Taras L Panikorovsky, Anna G Larina, Vitali M Boitsov, A V StepakovAbstract:3-Spiro[cyclopropa[a]pyrrolizine]- and 3-spiro[3-azabicyclo[3.1.0]hexane]oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and Cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro
Michael Rubin - One of the best experts on this subject based on the ideXlab platform.
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Directed Cu(I)-Catalyzed Carbomagnesiation of 1‑Arylcycloprop-2-ene-1-carboxamides En Route to Densely Substituted Functionalized Cyclopropanes
2018Co-Authors: Andrew Edwards, Michael RubinAbstract:Copper-catalyzed, directed addition of Grignard reagents across the strained CC bond of cyclopropene-3-carboxamides was developed. It was demonstrated that the amide functionality serves as an ultimate directing group allowing for highly efficient control of diastereoselectivity of addition including stereoselectivity of electrophilic trapping with prochiral aldehydes. Also, regioselectivity of carbomagnesiation of Cyclopropenes with a monosubstituted double bond is investigated. It was shown that in many cases this selectivity is controlled by steric factors and allows for preparation of products with a “reversed” regiochemistry
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one pot synthesis of gaba amides via the nucleophilic addition of amines to 3 3 disubstituted Cyclopropenes
Organic and Biomolecular Chemistry, 2015Co-Authors: Vladimir A Maslivetc, Marina Rubina, Michael RubinAbstract:A one-pot synthesis of various GABA amides has been demostrated, employing the nucleophilic addition of primary and secondary amines across the double bond of cyclopropene-3-carboxamides, followed by ring-opening of the resulting donor–acceptor cyclopropanes and subsequent in situ reduction of enamine (imine) intermediates.
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rearrangements of Cyclopropenes into five membered aromatic heterocycles mechanistic aspect
ChemInform, 2012Co-Authors: Michael Rubin, Pavel RyabchukAbstract:Due to significant strain in the small ring, Cyclopropenes are characterized by increased energy and a conformationally constrained hydrocarbon skeleton, which chiefly defines their unusually high reactivity and selectivity in reactions atypical for other unsaturated compounds. The increased electronic density of the π-system of its strained double bond makes cyclopropene a very attractive substrate for π-philic transition metals [1]]. In turn, this opens avenues for extremely rich coordination chemistry for different types of catalytic rearrangements, as well as for addition and cycloaddition reactions. The important role of small cycles in the photochemistry of furans was first demonstrated in reports by Srinivason [2, 3] and van Tamelen [4, 5], who discovered that the photo-rearrangement of 2-methylfurans 1 into 3-methylfurans 2 proceeds via a valent rearrangement forming 3-acylcyclopropene intermediate 3 (Scheme 1). In addition, in the reaction of furan 1а a competing photodecarbonylation leading to product 4 was detected, which confirmed the formation of intermediate 3-formylcyclopropene 3а (Scheme 1). Scheme 1
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Synthesis of Cyclopropenes via1,2-Elimination of Bromocyclopropanes Catalyzed by CrownEther
Synthesis, 2009Co-Authors: William M. Sherrill, Ryan Kim, Michael RubinAbstract:A new synthetic protocol for the preparation of 3,3-disubstituted Cyclopropenes from the corresponding bromocyclopropanes via a base-assisted 1,2-elimination has been developed. Employment of catalytic amounts of 18-crown-6 in ethereal solvents allowed for improved yields, as compared to the classical procedure employing dimethyl sulfoxide, making this protocol applicable to the synthesis of hydrophilic Cyclopropenes. The application of this new method for the efficient synthesis of cyclopropene-3-carboxamides, an important class of functionalized 3,3-disubstituted Cyclopropenes, is demonstrated. Scope and limitation studies are discussed.
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palladium catalyzed hydrophosphorylation and hydrophosphinylation of Cyclopropenes
ChemInform, 2008Co-Authors: Bassam K Alnasleh, William M. Sherrill, Michael RubinAbstract:Novel transition-metal-catalyzed addition of P−H entities across the cyclopropene double bond has been developed. This transformation allows for mild and efficient preparation of phosphorus-containing cyclopropanes in good yields and high degrees of diastereoselectivity.
Alexander P. Molchanov - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Functionalized 3‑Spiro[cyclopropa[a]pyrrolizine]- and 3‑Spiro[3-azabicyclo[3.1.0]hexane]oxindoles from Cyclopropenes and Azomethine Ylides via [3 + 2]-Cycloaddition
2016Co-Authors: Alexander S. Filatov, Rafael R. Kostikov, Alexander P. Molchanov, Nickolay A Knyazev, Taras L Panikorovsky, Anna G Larina, Vitali M Boitsov, A V StepakovAbstract:3-Spiro[cyclopropa[a]pyrrolizine]- and 3-spiro[3-azabicyclo[3.1.0]hexane]oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and Cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro
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Cyclopropenes in the 1,3-Dipolar Cycloaddition with Carbonyl Ylides: Experimental and Theoretical Evidence for the Enhancement of σ-Withdrawal in 3-Substituted-Cyclopropenes
The Journal of organic chemistry, 2006Co-Authors: Vyacheslav V. Diev, Rafael R. Kostikov, Rolf Gleiter, Alexander P. MolchanovAbstract:The carbonyl ylide dipoles generated by the dirhodium tetra-acetate-catalyzed decomposition of diazocarbonyl precursors 1, 5, and 8 cycloadd to 3-substituted 1,2-diphenylCyclopropenes 3a-e and 3,3-disubstituted Cyclopropenes 13, 14, 19, and 20 to give polycyclic compounds with 8-oxatricyclo[3.2.1.0(2,4)]octane and 9-oxatricyclo[3.3.1.0(2,4)]nonane frameworks. Generally, reactions proceed stereoselectively to give adducts of exo stereochemistry with the approach of the carbonyl ylide dipoles from the less-hindered face of Cyclopropenes. The electronic properties of the substituent at the C3 position of Cyclopropenes play an important role in governing the reactivity of Cyclopropenes: when the C3 position is substituted by electron-acceptors such as the methoxycarbonyl or cyano groups, the yields of adducts are decreased significantly or no adducts can be detected at all. Relative reactivities of Cyclopropenes were quantified by competition experiments to give the best correlation with sigmaF-Taft constants. Both measured photoelectron spectra and ground-state calculations of a series of 1,2-diphenylCyclopropenes indicate considerable lowering of cyclopropene pi-HOMO energies by substitution with an acceptor group. Such changes in electronic structures of Cyclopropenes may cause the inversion of frontier molecular orbital (FMO) interactions from HOMO(cyclopropene)-LUMO(ylide) to LUMO(cyclopropene)-HOMO(ylide) type. In terms of philicity, nucleophilic properties of acceptor-substituted Cyclopropenes are diminished to such an extent that these species are no longer good nucleophiles in the reaction with carbonyl ylides, and neither are they good electrophiles, being unreactive. This was shown by the B3LYP calculations of addends.
Ilan Marek - One of the best experts on this subject based on the ideXlab platform.
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Diastereo- and enantioselective preparation of cyclopropanol derivatives
Beilstein-Institut, 2019Co-Authors: Marwan Simaan, Ilan MarekAbstract:The diastereoselective carbocupration reaction of alkoxy-functionalized cyclopropene derivatives, followed by a subsequent trapping of the resulting cyclopropylmetal species with an electrophilic source of oxygen (oxenoid) afforded various tetrasubstituted cyclopropanol derivatives in high diastereo- and enantiomeric ratios. Similarly, the enantioselective copper-catalyzed carbomagnesiation/oxidation (or amination) sequence on achiral nonfunctionalized Cyclopropenes provided the desired cyclopropanol (and cyclopropylamine) derivatives in excellent diastereo- and enantiomeric excesses
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asymmetric copper catalyzed carbomagnesiation of Cyclopropenes
Angewandte Chemie, 2017Co-Authors: Longyang Dian, Daniel S. Müller, Ilan MarekAbstract:The highly diastereo- and enantioselective formation of polysubstituted cyclopropanes was easily achieved through the asymmetric copper-catalyzed carbomagnesiation reaction of nonfunctionalized cyclopropene derivatives. The carbometalated species generated in situ readily undergo C−C and C−X bond-forming reactions with various electrophiles with complete retention of configuration.
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Asymmetric Copper-Catalyzed Carbozincation of Cyclopropenes en Route to the Formation of Diastereo- and Enantiomerically Enriched Polysubstituted Cyclopropanes
Journal of the American Chemical Society, 2015Co-Authors: Daniel S. Müller, Ilan MarekAbstract:The enantioselective synthesis of cyclopropylzinc reagents has been achieved via a copper-catalyzed carbozincation of 3,3-disubstituted Cyclopropenes with diorganozinc reagents. The obtained organozinc compounds can be easily functionalized with a broad range of electrophiles, including palladium-catalyzed cross-couplings, affording highly substituted cyclopropanes. The operationally simple procedure using very low quantities of a commercially available and inexpensive copper catalyst provides a new tool for the synthesis of highly enantioenriched cyclopropanes as single diastereoisomers.
Vitali M Boitsov - One of the best experts on this subject based on the ideXlab platform.
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Stereo- and Regioselective 1,3-Dipolar Cycloaddition of the Stable Ninhydrin-Derived Azomethine Ylide to Cyclopropenes: Trapping of Unstable Cyclopropene Dipolarophiles
2019Co-Authors: Alexander S. Filatov, Anna G Larina, Vitali M Boitsov, Siqi Wang, Olesya V. Khoroshilova, Stanislav V. Lozovskiy, A V StepakovAbstract:A stereo- and regioselective 1,3-dipolar cycloaddition of the stable ninhydrin-derived azomethine ylide [2-(3,4-dihydro-2H-pyrrolium-1-yl)-1-oxo-1H-inden-3-olate, DHPO] to differently substituted Cyclopropenes has been established. As a result, an efficient synthetic protocol was developed for the preparation of biologically relevant spiro[cyclopropa[a]pyrrolizine-2,2′-indene] derivatives. DHPO has proved to be an effective trap for such highly reactive and unstable substrates as parent cyclopropene, 1-methylcyclopropene, 1-phenylcyclopropene, and 1-halo-2-phenylCyclopropenes. It has also been found that 3-nitro-1,2-diphenylcyclopropene undergoes a nucleophilic substitution reaction in alcohols and thiols to afford 3-alkoxy- and 3-arylthio-substituted 1,2-diphenylCyclopropenes, which can be captured as corresponding 1,3-dipolar cycloadducts in the presence of DHPO. These new approaches provide a straightforward strategy for the synthesis of functionally substituted cyclopropa[a]pyrrolizine derivatives. The factors governing regio- and stereoselectivity have been revealed by means of quantum mechanical calculations (M11 density functional theory), including previously unreported Nylide–Hcyclopropene second-orbital interactions. The outcome of this work contributes to the study of 1,3-dipolar cycloaddition, as well as enriches chemistry of Cyclopropenes and methods for the construction of polycyclic compounds with cyclopropane fragments
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synthesis of functionalized 3 spiro cyclopropa a pyrrolizine and 3 spiro 3 azabicyclo 3 1 0 hexane oxindoles from Cyclopropenes and azomethine ylides via 3 2 cycloaddition
Journal of Organic Chemistry, 2017Co-Authors: Alexander S Filatov, Nickolay A Knyazev, A P Molchanov, Taras L Panikorovsky, R R Kostikov, Anna G Larina, Vitali M Boitsov, A V StepakovAbstract:3-Spiro[cyclopropa[a]pyrrolizine]- and 3-spiro[3-azabicyclo[3.1.0]hexane]oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and Cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro.
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Synthesis of Functionalized 3‑Spiro[cyclopropa[a]pyrrolizine]- and 3‑Spiro[3-azabicyclo[3.1.0]hexane]oxindoles from Cyclopropenes and Azomethine Ylides via [3 + 2]-Cycloaddition
2016Co-Authors: Alexander S. Filatov, Rafael R. Kostikov, Alexander P. Molchanov, Nickolay A Knyazev, Taras L Panikorovsky, Anna G Larina, Vitali M Boitsov, A V StepakovAbstract:3-Spiro[cyclopropa[a]pyrrolizine]- and 3-spiro[3-azabicyclo[3.1.0]hexane]oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and Cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro
