Synthesis of New Captodative Alkenes: Alkyl 2-Aroyloxy Acrylates − Structure, and Reactivity in Diels−Alder Cycloadditions

Herrera, Rafael; Jiménez‐Vázquez, Hugo A.; Modelli, Alberto; Jones, Derek; Söderberg, Björn C.G.; Tamariz, Joaquı́n

doi:10.1002/1099-0690(200112)2001:24<4657::aid-ejoc4657>3.0.co;2-3

Cited by 21 publications

(25 citation statements)

References 10 publications

(33 reference statements)

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“…This behavior is not unexpected, considering that the ester carbonyl group has a lesser electron-withdrawing effect than the ketone carbonyl group. 6 This would support the hypothesis that the reactivity of this kind of captodative olefins is controlled mainly by the electronic effect of the electronwithdrawing group. 5 Olefin 1a reacts with furan (9) under Lewis acid catalysis to give the Friedel-Crafts product, the aromatic electrophilic substitution taking place at the C-2 carbon of the heterocycle.…”

Section: Diels-alder and Friedel-crafts Reactions Of Olefins 3a And 3bsupporting

confidence: 63%

“…Soc. conjugated moieties (a) and (b) were, nevertheless, perpendicular to each other, paralleling the preferred conformations found for 1a and other captodative olefins. 6 The four possible s-cis/s-trans conformers of both alkenes had similar energies, spanning a small energy range (0.42 kcal mol -1 for 3a, and 1.16 kcal mol -1 for 3b; Table 1). Although these energy differences are not large enough to claim that one of the conformers is totally favored in the gas phase, it has been established that, for analogous small energy differences, the solid-state conformation of the conjugated acrylate system of alkene 1d, shows good agreement with the calculated gas phase structure.…”

Section: Preparation Of the Captodative Olefins 1-acetylvinyl Acrylatmentioning

confidence: 99%

“…Although these energy differences are not large enough to claim that one of the conformers is totally favored in the gas phase, it has been established that, for analogous small energy differences, the solid-state conformation of the conjugated acrylate system of alkene 1d, shows good agreement with the calculated gas phase structure. 6…”

Section: Preparation Of the Captodative Olefins 1-acetylvinyl Acrylatmentioning

confidence: 99%

“…The reactivity and selectivity of these olefins in Diels-Alder reactions were evaluated under thermal and catalytic conditions, using cyclopentadiene (6) as the diene (Table 2). Both exo and endo stereoisomers, 7 and 8, were obtained under mild thermal conditions (Scheme 2), showing a small preference for the exo isomers 7a and 7b ( Table 2, entries 1 and 11).…”

Section: Diels-alder and Friedel-crafts Reactions Of Olefins 3a And 3bmentioning

confidence: 99%

“…Hartree-Fock (HF/ 6-31G(d,p)) and DFT (B3LYP/ 6-311G(d,p)) calculations were carried out to determine the most stable conformers of 3a and 3b, and to evaluate the relative energies of the unoccupied MOs expected to be involved in the reactivity of these processes. In addition, in order to obtain a better understanding of the exo stereoselectivity commonly observed in the cycloaddition reactions of captodative olefins, we have determined (B3LYP/6-311G(d,p)) some of the possible transition states in the Diels-Alder reaction of 3a and 3b with cyclopentadiene (6).…”

Section: Introductionmentioning

confidence: 99%

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1-acetylvinyl acrylates: new captodative olefins bearing an internal probe for the evaluation of the relative reactivity of captodative against electron-deficient double bonds in Diels-Alder and Friedel-Crafts reactions

Herrera

Jiménez‐Vázquez

Delgado

et al. 2005

J. Braz. Chem. Soc.

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As olefinas captodativas 3a e 3b derivadas dos ácidos metacrílico e trans-crotônico foram preparadas. A presença de uma segunda ligação dupla na molécula, atuando como marcador interno, permitiu-nos comparar sua reatividade relativa em reações de Diesl-Alder e Friedel-Crafts. A reatividade foi avaliada com ciclopentadieno (6) atuando como dieno em cicloadição Diels-Alder, e com furano (9) e tiofeno (10) como substratos heteroaromáticos Friedel-Crafts. Em ambos os processos, a ligação dupla da enona captodativa mostrou-se mais reativa que a do sistema acrílico. A teoria FMO considera essa quimiosseletividade como consequência da maior contribuição da enona ao orbital LUMO dessas moléculas. A pequena seletividade exo observada na cicloadição com 6 concorda com a maior estabilidade do estado de transição, de acordo com os resultados de cálculos B3LYP/6-311G(d,p).The captodative olefins 1-acetylvinyl esters of methacrylic and trans-crotonic acids, 3a and 3b, have been prepared. The presence of a second double bond in the molecule, acting as an internal probe, allowed us to compare their relative reactivity in Diels-Alder and Friedel-Crafts reactions. The reactivity was evaluated with cyclopentadiene (6) as diene in Diels-Alder cycloadditions, and with furan (9) and thiophene (10) as heteroaromatic Friedel-Crafts substrates. In both processes, the captodative enone double bond proved to be more reactive than that in the acrylic moiety. FMO theory accounted for this chemoselectivity as a consequence of the major contribution of the enone to the LUMO of these molecules. The slight exo stereoselectivity observed in the cycloaddition to 6 parallels the higher stability of the corresponding transition state, according to the results of B3LYP/ 6-311G(d,p) calculations.

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Section: Diels-alder and Friedel-crafts Reactions Of Olefins 3a And 3bsupporting

confidence: 63%

Section: Preparation Of the Captodative Olefins 1-acetylvinyl Acrylatmentioning

confidence: 99%

Section: Preparation Of the Captodative Olefins 1-acetylvinyl Acrylatmentioning

confidence: 99%

Section: Diels-alder and Friedel-crafts Reactions Of Olefins 3a And 3bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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1-acetylvinyl acrylates: new captodative olefins bearing an internal probe for the evaluation of the relative reactivity of captodative against electron-deficient double bonds in Diels-Alder and Friedel-Crafts reactions

Herrera

Jiménez‐Vázquez

Delgado

et al. 2005

J. Braz. Chem. Soc.

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ChemInform Abstract: Synthesis of New Captodative Alkenes: Alkyl 2‐Aroyloxy Acrylates — Structure, and Reactivity in Diels—Alder Cycloadditions.

Herrera¹,

Jiménez‐Vázquez²,

Modelli³

et al. 2002

ChemInform

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Selectivity in 1,3‐Dipolar Cycloadditions of β‐Substituted Captodative Olefins – An Experimental and DFT Transition State Study

Herrera

Mendoza²,

Morales

et al. 2007

Eur J Org Chem

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Captodative olefins 1‐acetylvinyl carboxylates substituted with alkyl groups at theposition, 12, strongly modified the regioselectivity of 1,3‐dipolar cycloadditions with respect to the behavior observed for their unsubstituted analogs, 1. When the reaction of 12 was carried out with diphenyl nitrone (7a), the corresponding C‐4 disubstituted isoxazolidines were obtained as a mixture or as single stereoisomers, in contrast to the isomeric C‐5 disubstituted heterocycles yielded by olefins 1. Nevertheless, olefins 12 reacted with benzonitrile oxide (2a) to give the C‐5 acetyl isoxazoles, as observed with dipolarophiles 1. This intricate behavior of the reactions between 1,3‐dipoles and β‐substituted captodative olefins was rationalized on the basis of DFT calculations [B3LYP/6‐31(d)] of the transition states (TSs) for nitrone 7a and olefin 12a. Thus, the observed C‐4 and endo regio‐ and stereoselectivities agreed with the most stable TSs, which are mainly stabilized by dipolar and electrostatic interactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Synthesis of New Captodative Alkenes: Alkyl 2-Aroyloxy Acrylates − Structure, and Reactivity in Diels−Alder Cycloadditions

Cited by 21 publications

References 10 publications

1-acetylvinyl acrylates: new captodative olefins bearing an internal probe for the evaluation of the relative reactivity of captodative against electron-deficient double bonds in Diels-Alder and Friedel-Crafts reactions

1-acetylvinyl acrylates: new captodative olefins bearing an internal probe for the evaluation of the relative reactivity of captodative against electron-deficient double bonds in Diels-Alder and Friedel-Crafts reactions

ChemInform Abstract: Synthesis of New Captodative Alkenes: Alkyl 2‐Aroyloxy Acrylates — Structure, and Reactivity in Diels—Alder Cycloadditions.

Selectivity in 1,3‐Dipolar Cycloadditions of β‐Substituted Captodative Olefins – An Experimental and DFT Transition State Study

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