scholarly journals The evaluation of chemoselectivity in multicomponent domino Knoevenagel/Diels-Alder reaction: A DFT study

2021 ◽  
pp. 66-66
Author(s):  
Mina Attarbashi ◽  
Shiraz Zabarjad ◽  
Marjaneh Samadizadeh
Keyword(s):  
Theoretical Calculations ◽  
Alder Reaction ◽  
Diels Alder ◽  
Acid Base ◽  
Bond Rotation ◽  
Solvent Phase ◽  
Diels Alder Reaction ◽  
Meldrum Acid ◽  
Predominant Product ◽  
Clear Information

Herein, the chemoselectivity of the multicomponent domino Knoevenagel/Diels-Alder reaction is investigated in terms of theoretical calculations. Structures of reagents, transition states, intermediates and products are optimized at the M062X/6-31+G(d,p) level of theory. The reaction mechanism involves processes of bond rotation, isomerization, asymmetric cycloaddition, acid-base and nucleophile-electrophile competitions, which are studied to deliver a clear information of the mechanism in terms of chemoselectivity considerations. Accordingly, the chemoselectivity of the reaction is controlled by the releasing acetone during the decomposition of Meldrum acid in the presence of methanol and L-proline (DG# = 61.45 kcal mol-1). Comparing calculated results (gas and solvent phase) with the experimental ones showed that utilizing these reagents are the kinetical favorite path for the chemoselective multicomponent cascade Knoevenagel/Diels-Alder reaction to produce the predominant product (>95 %). The results suggest that the creation of cis-spiro cyclohexanone is the predominant chemoselective product under kinetic control of the desired enone.

DFT studies on the diastereoselectivity and regioselectivity of multicomponent domino Knoevenagel/Diels–Alder reaction

2020 ◽  
Vol 19 (02) ◽  
pp. 2050005 ◽  
Author(s):  
Mina Attarbashi ◽  
Nader Zabarjad Shiraz ◽  
Marjaneh Samadizadeh
Keyword(s):  
Gas Phase ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ring Closure ◽  
Dft Studies ◽  
Acid Base ◽  
Bond Rotation ◽  
Diels Alder Reaction ◽  
Difference Formula ◽  
State Formula

In this study, mechanism and stereochemistry of multicomponent domino Knoevenagel/Diels–Alder reaction were investigated theoretically. Structures of reagents, transition states, intermediates, and products were optimized at M062X/6-31[Formula: see text]G(d,p) level of theory. Although the mechanism of this reaction involved several processes, including bond rotation, isomerization, asymmetric cycloaddition, acid-base, and nucleophile–electrophile competitions, critical processes were studied to provide a clearer picture of the mechanism of this valuable reaction in terms of stereochemistry considerations. According to the results, the ring closure step of reaction performed via a polar Dield-Alder mechanism, having enthalpy at approximately 40[Formula: see text]kcal/mol. The diastereoselectivity of the reaction was controlled by the interaction of dienophile with the less hindered face of diene through a more stable endo transition state ([Formula: see text] and 27.31 in methanol and gas phase, respectively). HSAB criteria could explain the regioselectivity of this reaction by considering the least softness difference ([Formula: see text]) for interacting C-atoms based on Hirshfeld populations. The result was the creation of cis-spiro cyclohexanone under kinetic and thermodynamic controls as a predominant diastereoselective and regioselective product.

Synthèse d'aryl nitronorbornènes par cycloaddition de Diels–Alder entre les aryl-nitroéthylènes et le cyclopentadiène. Justification de la stéréochimie et de la réactivité relative observées par la méthode CNDO/II. Obtention d'aryl aminonorbornènes

1985 ◽  
Vol 63 (9) ◽  
pp. 2354-2361 ◽  
Author(s):  
Jean Bourguignon ◽  
Gilles Le Nard ◽  
Guy Queguiner
Keyword(s):  
Theoretical Calculations ◽  
Alder Reaction ◽  
Diels Alder ◽  
Relative Reactivity ◽  
H Nmr ◽  
Diels Alder Reaction

Syntheses of numerous 2-aryl nitroethylenes (nitrostyrenes) have been optimized. The nitrostyrenes have been reacted with cyclopentadiene in Diels–Alder cycloadditions and the 3-aryl 2-nitronorbornenes obtained have been reduced into 3-aryl 2-aminonorbornenes. These compounds are potentially dopaminergic molecules. The stereochemistry of the adducts obtained in the Diels–Alder reaction has been determined by 1H nmr. The stereochemistry and the relative reactivity of the nitrostyrenes versus cyclopentadiene have been confirmed by theoretical calculations based on the CNDO/II method.

Organic reactions in liquid crystalline solvents. 2. An investigation into the use of liquid crystalline solvents to effect stereochemical control in the Diels–Alder reaction

1985 ◽  
Vol 63 (10) ◽  
pp. 2736-2741 ◽  
Author(s):  
William J. Leigh
Keyword(s):  
Liquid Crystalline ◽  
Transition States ◽  
Alder Reaction ◽  
Diels Alder ◽  
Shape Transition ◽  
Bimolecular Reactions ◽  
Solvent Phase ◽  
Stereochemical Control ◽  
Diels Alder Reaction ◽  
Liquid Crystalline Phases

The possibility of using liquid crystalline solvents to control the stereospecificity of bimolecular reactions as a result of differences in liquid crystalline solvation of the various possible transition states has been examined. The Diels–Alder reactions of 2,5-dimethyl-3,4-diphenylcyclopentadienone with four dienophiles of varying steric size (cyclopentene, cycloheptene, indene, and acenaphthylene) have been carried out in benzene, cholesteryl nonanoate (isotropic), cholesteryl propionate (cholesteric), and 4-ethyl-4′-(4-pentylcyclohexyl)biphenyl (smectic) at 105 °C. In spite of very large differences in steric solvation requirements for the endo- (globular in shape) and exo- (plate-like in shape) transition states in these reactions, no variation in product ratio with solvent phase is observed in any case.The inability of the ordered liquid crystalline phases to differentiate between endo- and exo-transition states in the Diels–Alder reactions investigated is rationalized as being the possible result of several factors. The most important of these are believed to be free volume effects, owing to both inefficient steric solvation of the bulky diene and volume contraction in the transition states for cycloaddition.

Envisioning an enzymatic Diels–Alder reaction by in situ acid–base catalyzed diene generation

2012 ◽  
Vol 48 (45) ◽  
pp. 5665 ◽  
Author(s):  
Mats Linder ◽  
Adam Johannes Johansson ◽  
Bianca Manta ◽  
Philip Olsson ◽  
Tore Brinck
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Acid Base ◽  
Diels Alder Reaction

scholarly journals A DFT investigation of Diels-Alder reaction of ethyl propiolate to the cage-annulated hexacyclo[7.5.2.01,6.06,13.08,12.010,14]hexadeca-2,4-diene-7,16-dione

2018 ◽  
Vol 83 (7-8) ◽  
pp. 837-846
Author(s):  
Abdurrahman Atalay ◽  
Riza Abbasoglu
Keyword(s):  
Theoretical Calculations ◽  
Cycloaddition Reaction ◽  
Dft Method ◽  
Alder Reaction ◽  
Diels Alder ◽  
Frontier Molecular Orbital ◽  
Kinetic Control ◽  
Diels Alder Reaction ◽  
Potential Map ◽  
Good Agreement

The Diels?Alder (DA) reaction between the cage-annulated diene hexacyclo[7.5.2.01,6.06,13.08,12.010,14]hexadeca-2,4-diene-7,16-dione (HHDD) with a cyclohexa-1,3-diene moiety and ethyl propiolate (EP) dienophile was investigated by the DFT method at the B3LYP/6-31+G(d,p) level to elucidate the mechanism and regioselectivity features of the reaction. The geometrical and electronic structures of the caged diene HHDD and EP were studied at B3LYP/6-31+G(d,p) level. In order to identify facial- and regio-selectivity of the DA reaction of HHDD and EP, the frontier molecular orbital (FMO) interactions of the reactants according to the FMO theory, and the molecular electrostatic potential map of HHDD were examined. The potential energy surface (PES) of the related DA reaction was calculated, and optimizations of transition states and of products corresponding to critical points on the PES were performed at the B3LYP/6-31+G(d,p), and their configurations were determined. In addition, the thermodynamic and kinetic parameters of each possible cycloaddition reaction were calculated using the B3LYP/6-31+G(d,p) method to determine whether the reaction occurs under thermodynamic or kinetic control. The thermochemical results showed that the related DA cycloaddition proceeds under kinetic control, and the activation energies of syn cycloadditions are clearly lower than that of anti cycloadditions. The theoretical calculations are in good agreement with experimental results.

Regioselective Diels–Alder reaction to open-cage ketolactam derivatives of C60

2017 ◽  
Vol 15 (29) ◽  
pp. 6136-6146 ◽  
Author(s):  
Teruhiko Tanaka ◽  
Ryuichi Nojiri ◽  
Yoshiki Sugiyama ◽  
Ryouhei Sawai ◽  
Toshikazu Takahashi ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Derivatives Of ◽  
C Nmr

Open-cage ketolactam fullerenes reacted with dienes on the rim of the orifice both regio- and endo-selectively, which were confirmed by 2D INADEQUATE 13C NMR of 13C enriched material/HMBC spectra as well as the theoretical calculations.

The Diels-Alder Reaction of 2-Ethenyl-1,4-Benzodioxin: A New and Simple Synthesis of Bisaryl Ethers

Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 30-32
Author(s):  
Thomas V. Lee ◽  
Alistair J. Leigh ◽  
Christopher B. Chapleo
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Simple Synthesis ◽  
Diels Alder Reaction

The intermolecular anthracene-transfer in a regiospecific antipodal C60 difunctionalization

2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz
Keyword(s):  
Noncovalent Interactions ◽  
Interaction Model ◽  
Alder Reaction ◽  
Diels Alder ◽  
Stacking Interactions ◽  
Pi Stacking ◽  
Diels Alder Reaction ◽  
Double Decker ◽  
Anthracene Molecule ◽  
New Strategies

We analyze the mechanism of the topochemically controlled difunctionalization of C60 and anthracene, where an anthracene molecule is transferred from one C60 monoadduct to another one under exclusive formation of equal amounts of C60 and the difficult to make antipodal C60 bisadduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates from one fullerene under formation of an intermediate, while already undergoing stabilizing interactions with both neighboring fullerenes, facilitating the reaction kinetically. In the intermediate, a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong "double-decker" type pi-pi stacking interactions with both of these fullerenes. Analysis with the distorsion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distorsions. This analysis sheds light on the existence of noncovalent interactions engaging both faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented 'inverted sandwich' structure. Hence, it sheds light on new strategies to design functional fullerene based materials.<br>

Natural Products Biosynthesis Involving a Putative Diels-Alder Reaction

2016 ◽  
Vol 20 (22) ◽  
pp. 2421-2442 ◽  
Author(s):  
Kévin Cottet ◽  
Maria Kolympadi ◽  
Dean Markovic ◽  
Marie-Christine Lallemand
Keyword(s):  
Natural Products ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction
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