Stereocontrolled Diels–Alder reactions with a bifunctional dienophile

Kakushima, Masatoshi; Scott, David

doi:10.1139/v79-228

Cited by 18 publications

(2 citation statements)

References 3 publications

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“…The small energy differences that are responsible for either high endo or high exo selectivity complicate the theoretical rationalization of the problem because the observed final effect can be the sum of several different contributions. Secondary orbital overlap in the endo transition structures and steric , or solvent , effects have been suggested as an explanation of the experimental results.…”

Section: Resultsmentioning

confidence: 98%

Cyclic Vinyl p-Tolyl Sulfilimines as Chiral Dienophiles: Theoretical Study on the Stereoselectivity, Lewis Acid Catalysis, and Solvent Effects in Their Diels−Alder Reactions

et al. 2002

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The theoretical study reported in the present work deals with chiral cyclic vinyl sulfilimines and their reactivity as dienophiles in [4 + 2] cycloaddition reactions, using B3LYP/6-31G(d)//AM1 and B3LYP/6-31G(d)//B3LYP/6-31G(d) model chemistries. Consideration of Lewis acid catalysis, illustrated by BF(3), decreases the activation energies of the cycloaddition process while the charge transfer from the diene to the sulfilimine is augmented. The [4 + 2] cycloaddition reactions of sulfilimines with both furan and cyclopentadiene occur in the gas phase with endo stereoselectivity, which is more pronounced with the latter diene. Endo-exo energy differences in the gas phase with the B3LYP/6-31+G(d)//B3LYP/6-31+G(d), B3LYP/6-31G(d)//B3LYP/6-31G(d), and B3LYP/6-31G(d)//AM1 model chemistries are almost the same. Solvent effects are responsible for the inversion of the stereoselectivity in the reactions of sulfilimines with furan because of the great difference in the dipole moments in endo and exo approaches.

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Section: Resultsmentioning

confidence: 98%

Cyclic Vinyl p-Tolyl Sulfilimines as Chiral Dienophiles: Theoretical Study on the Stereoselectivity, Lewis Acid Catalysis, and Solvent Effects in Their Diels−Alder Reactions

et al. 2002

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“…Dienophiles exhibiting kinetic exo -selectivity are not too frequent, and this feature is usually associated with secondary orbital overlap in the endo transition structures, solvent effects, or steric effects of the substituents destabilizing the endo approach . Nevertheless, in the case of dienophile 2 there do not exist such substituents, which suggests that the electrostatic interactions or the solvent effects must be responsible for the observed behavior.…”

Section: Resultsmentioning

confidence: 99%

Cyclic Vinyl p-Tolyl Sulfilimines as Chiral Dienophiles: Diels−Alder Reactions with Furan and Acyclic Dienes

et al. 2002

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The dienophilic behavior of the sulfilimine 2, synthesized from (Z)-3-p-tolylsulfinylacrylonitrile 1, in its Diels-Alder reactions with furan and acyclic dienes has been investigated. A complete pi-facial selectivity for 2, opposite to that observed from its precursor 1, is the main feature of all these cycloadditions. Moreover, the high exo selectivity observed in reactions of 2 with furan (not observed for 1) contrasts with the almost complete endo selectivity with other cyclic and acyclic dienes. Additionally, the opposite regioselectivities obtained for 2 with Dane's diene and 1-substituted butadienes (not observed for 1) are also noteworthy. This behavior allows dienophiles 1 and 2 to be considered as complementary precursors from a synthetic point of view.

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p-Toluenesulfonyl Isocyanate

Johnson¹

2001

Encyclopedia of Reagents for Organic Synthesis

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Stereocontrolled Diels–Alder reactions with a bifunctional dienophile

Abstract: In the Diels–Alder cycloaddition of electron-rich dienes to methyl E-4-oxobutenoate, the formyl group controls both regio- and stereoselectivity. Secondary overlap considerations are used to explain these results.

Cited by 18 publications

References 3 publications

Cyclic Vinyl p-Tolyl Sulfilimines as Chiral Dienophiles: Theoretical Study on the Stereoselectivity, Lewis Acid Catalysis, and Solvent Effects in Their Diels−Alder Reactions

Cyclic Vinyl p-Tolyl Sulfilimines as Chiral Dienophiles: Theoretical Study on the Stereoselectivity, Lewis Acid Catalysis, and Solvent Effects in Their Diels−Alder Reactions

Cyclic Vinyl p-Tolyl Sulfilimines as Chiral Dienophiles: Diels−Alder Reactions with Furan and Acyclic Dienes

p-Toluenesulfonyl Isocyanate

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