Search results for "Ylide"
showing 10 items of 1084 documents
CCDC 2155455: Experimental Crystal Structure Determination
2022
Related Article: Estefanía Tiburcio, Yongkun Zheng, Marta Mon, Nuria Martín, Jesús Ferrando−Soria, Donatella Armentano, Antonio Leyva−Pérez, Emilio Pardo|2022|Inorg.Chem.|61|11796|doi:10.1021/acs.inorgchem.2c01508
CCDC 1414395: Experimental Crystal Structure Determination
2016
Related Article: Marta Mon, Alejandro Pascual-Álvarez, Thais Grancha, Joan Cano, Jesús Ferrando-Soria, Francesc Lloret, Jorge Gascon, Jorge Pasán, Donatella Armentano, Emilio Pardo|2016|Chem.-Eur.J.|22|539|doi:10.1002/chem.201504176
CCDC 2128260: Experimental Crystal Structure Determination
2022
Related Article: Mariafrancesca Baratta, Teresa Fina Mastropietro, Rosaria Bruno, Antonio Tursi, Cristina Negro, Jesús Ferrando-Soria, Alexander I. Mashin, Aleksey Nezhdanov, Fiore P. Nicoletta, Giovanni De Filpo, Emilio Pardo, Donatella Armentano|2022|ACS Appl. Nano Mater.|5|5223|doi:10.1021/acsanm.2c00280
CCDC 2122007: Experimental Crystal Structure Determination
2022
Related Article: Cristina Negro, Cristina Bilanin, Xiaoni Qu, Judit Oliver-Meseguer, Jesús Ferrando-Soria, Antonio Leyva-Pérez, Donatella Armentano, Emilio Pardo|2022|Chem.Commun.|58|5578|doi:10.1039/D2CC01137A
1,3-Dipolar cycloadditions with meso-tetraarylchlorins – site selectivity and mixed bisadducts
2017
The 1,3-dipolar cycloaddition reaction of meso-tetraarylporphyrins with nitrones gives isoxazolidine-fused chlorins. Depending on the substitution pattern on the meso-aryl groups and the nitrone, the chlorins can be obtained in high yields (up to 91%). Bacteriochlorin-type bisadducts are also obtained, although in low yield, from the reaction of meso-tetrakis(pentafluorophenyl)porphyrin with N-methyl, N-cyclohexyl or N-benzyl nitrone. The structure of a bis(N-benzyl isoxazolidine-fused) bacteriochlorin was determined by single-crystal X-ray diffraction and rationalized by DFT calculations. To further explore the nature of site selectivity in the formation of bisadducts, isomeric mixed bacte…
Experimental and theoretical study of the [3+2] cycloaddition of carbonyl ylides with alkynes
2012
[EN] The [3 + 2] cycloaddition reaction between carbonyl ylides generated from epoxides and alkynes (phenylacetylene, methyl propiolate, methyl but-2-ynoate and methyl 3-phenylpropiolate) to give substituted 2,5-dihydrofurans was investigated. The effect of indium(III) chloride on the outcome of the reaction was studied in the case of phenylacetylene and methyl propiolate. The thermal reaction between the carbonyl ylide coming from 2,2-dicyano-3-phenyloxirane and both methyl propiolate and methyl but-2-ynoate was theoretically investigated using DFT methods in order to explain the reactivity and regioselectivity observed.
A Close Look to the Oxaphosphetane Formation along the Wittig Reaction: A [2+2] Cycloaddition?
2020
The Wittig reaction between triphenylphosphine methylide and benzaldehyde has been studied both from conceptual and computational approaches. The supernucleophilic character of ylide accounts for the feasibility of the initial nucleophilic attack. The nature of bonding driving the formation of the first oxaphosphetane (OPA) intermediate in such a domino reaction is examined within a topological-based bonding evolution theory perspective. The sequence of the electronic flow associated to the changes in electron density supports a rationalization via two main electronic stages characterizing the single kinetic step: first, the C-C bond formation, which takes place via donation of electron den…
Unveiling the high reactivity of benzyne in the formal [3+2] cycloaddition reactions towards thioamides through the Molecular Electron Density Theory
2020
Abstract The domino reaction of benzyne with thioamide has been studied within the Molecular Electron Density Theory (MEDT) at the MPWB1K/6-311G(d) level. This domino reaction takes place through i) a formal [3 + 2] cycloaddition (32CA) reaction affording an ammonium ylide, and ii) an extrusion of ethylene from this species yielding a dihydrothiazole. Topological analysis of the electron density of benzyne shows its pseudodiradical structure, that is, without any energy cost, changes to a carbenoid one, allowing its participation as electrophile in polar reactions. As a consequence, the formal 32CA reaction does not have an activation enthalpy. Analysis of the changes of electron density al…
A combined experimental and theoretical study of the polar [3+2] cycloaddition of electrophilically activated carbonyl ylides with aldehydes and imin…
2009
International audience; Numerous 2,5-diaryl-1,3-dioxolane-4,4-dicarbonitriles and 2,4-diphenyl-1,3-oxazolidine-5,5- dicarbonitriles have been synthesized by [3+2] cycloaddition reactions between carbonyl ylides generated from epoxides, and aldehydes or imines. In contrast to the use of aldehydes (3,4,5- trimethoxybenzaldehyde, piperonal, 1-naphthaldehyde, indole-3-carboxaldehyde, furan-2- carboxaldehyde and thiophene-2-carboxaldehyde), the reactions performed with imines (N- (phenylmethylene)methanamine, N-(1,3-benzodioxol-5-ylmethylene)propylamine, N-(1,3-benzodioxol- 5-ylmethylene)butylamine and N-(1,3-benzodioxol-5-ylmethylene)benzylamine) proceed diastereoselectively. The effect of micr…
ChemInform Abstract: Ring Expansion of 1,2,3,4-Tetrahydroisoquinolines to Dibenzo[c,f]azonines. An Unexpected [1,4]-Sigmatropic Rearrangement of Nitr…
2014
When the products of a Strecker reaction of 1,2,3,4-tetrahydroisoquinolines with aromatic aldehydes are quaternized with alkyl triflates and subsequently treated with base, a ring expansion to 6,7,8,13-tetrahydro-5H-dibenzo[c,f]azonine-5-carbonitriles takes place. The nine-membered cyclic products can be obtained in good yields (78–89%) in a process involving the [1,4]-sigmatropic rearrangement of a nitrile-stabilized ammonium ylide. The reaction sequence provides a new, simple, and efficient method for the synthesis of these unusual N-heterocycles.