Stereoselective synthesis, NMR conformational study and Diels-Alder reaction of β-functionalized 1-acetylvinyl arenecarboxylates

Peralta, Javier; Bullock, Joseph P.; Bates, Roderick W.; Bott, Simon G.; Zepeda, L. Gerardo; Tamariz, Joaquı́n

doi:10.1016/0040-4020(95)00140-4

Cited by 21 publications

(5 citation statements)

References 70 publications

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“…However, the presence of a methyl group in the β-position in carbene 6 E produced a large effect, inhibiting addition to 1 under the same experimental conditions (20 h) and providing only the oxidation ester 20 . This result is in agreement with previous reports that show deactivation of the double bond in Diels−Alder cycloadditions of β-substituted captodative olefins . The moderate yields obtained in the reaction of carbene 3 with cyclopentadiene ( 1 ) were increased when the reaction was carried out at 40 °C.…”

Section: Resultssupporting

confidence: 93%

High Stereoselectivity and Facial Selectivity in Diels−Alder Cycloadditions of Novel Captodative Olefins: α-Alkoxyvinyl(ethoxy)carbene Chromium Complexes with Cyclopentadienes

et al. 2004

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A study of reactivity and selectivity of the new Fischer carbene complexes (CO)5CrC[C(CHR‘)(OR)]OCH2CH3 (3, R‘ = H, R = CH2CH3; 4, R‘ = H, R = CH2CH2CH3; 5, R‘ = H, R = CH2CH2CH2CH3; 6, R‘ = CH3 (E and Z), R = CH2CH3) was carried out in Diels−Alder cycloadditions with cyclopentadiene (1) and 1,2,3,4,5-pentamethylcyclopentadiene (7). The cycloadditions between the α-alkoxyvinyl(ethoxy)carbene complexes 3, 4, and 5 with 1 were found to be highly stereoselective, favoring the endo adduct at a much higher level than that observed for the analogous α-alkoxy-α,β-unsaturated esters, whereas complex 6 E showed low reactivity. When 1,2,3,4,5-pentamethylcyclopentadiene (7) was employed, the cycloadditions with α-alkoxyvinyl(ethoxy)carbene complexes 3−6 E were highly anti/exo selective. The exo adducts form new alkoxy-chelated tetracarbonyl carbene complexes. The stereochemical assignment of the cycloadducts was supported by NOE measurements, and the chelated exo cycloadduct 21 was further characterized by single-crystal X-ray diffraction.

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Section: Resultssupporting

confidence: 93%

High Stereoselectivity and Facial Selectivity in Diels−Alder Cycloadditions of Novel Captodative Olefins: α-Alkoxyvinyl(ethoxy)carbene Chromium Complexes with Cyclopentadienes

et al. 2004

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“…The larger angle in compound (3) possibly minimizes non-bonded contacts between the H6 and H2 atoms; these atoms are almost coplanar and lie only 2.03 (3) ,~, apart, whereas the corresponding H atoms in compound (4) are staggered. In agreement with this interpretation, particularly large C2---C3--N4 angles (>130 °) are found in enaminones containing substituents at the 2-position (Mague, De & Krogstad, 1995;Arriortua et al, 1992;Peralta et al, 1995). The N atom in both compounds (3) and (4) is planar; the angles around N4 total 359.8 (2) ° for the ordered component of (3) and 360.0 (3) ° for (4).…”

Section: Commentsupporting

confidence: 58%

Two C-Unsubstituted Enaminals

Blake¹,

McNab²,

Monahan³

et al. 1996

Acta Crystallogr C

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“…We have also assessed the perturbation effect of a third substituent at theposition of the double bond of 1 on the reactivity, regio‐, and stereoselectivity of these olefins in Diels–Alder reactions 12. We prepared β‐functionalized 1‐acetylvinyl arenecarboxylates 9 ; however, they failed to react with cyclopentadiene ( 10 ) and isoprene ( 11 ), except for β‐brominated olefin 9a , which undergoes addition to these dienes to give the exo and para adducts, respectively, as the major isomers (Scheme ) 12a. The ratio of regioisomers obtained with diene 11 , under thermal conditions, was similar to that observed for unsubstituted olefin 1a .…”

Section: Introductionmentioning

confidence: 52%

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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Stereoselective synthesis, NMR conformational study and Diels-Alder reaction of β-functionalized 1-acetylvinyl arenecarboxylates

Cited by 21 publications

References 70 publications

High Stereoselectivity and Facial Selectivity in Diels−Alder Cycloadditions of Novel Captodative Olefins: α-Alkoxyvinyl(ethoxy)carbene Chromium Complexes with Cyclopentadienes

High Stereoselectivity and Facial Selectivity in Diels−Alder Cycloadditions of Novel Captodative Olefins: α-Alkoxyvinyl(ethoxy)carbene Chromium Complexes with Cyclopentadienes

Two C-Unsubstituted Enaminals

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

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