Secondary deuterium isotope effects and transition state structure in the aromatic Claisen rearrangement

McMichael, Kirk D.; KORVER, G. L.

doi:10.1021/ja00504a051

Cited by 32 publications

(12 citation statements)

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“…A precedent does exist for rate enhancement in the Ireland-Claisen rearrangement with an electron-donating substituent in the C 6 position -Curran has shown [16] that the presence of an oxygen in this position leads to a rate acceleration effect of one or more orders of magnitude. This effect (which has been studied computationally [17] ) is rationalized as a "vinylogous anomeric" (π→σ * ) stabilization [16d,18] of the transition state, in that weakening of the O 3 -C 4 bond facilitates its cleavage upon going to an early transition state [19,20] in which bond-breaking may be [21] significantly more advanced than bond-making (Scheme 9). The observations that an oxygen at the C 4 position leads to a similar rate acceleration [16e] and that solvent effects [16e,20c] and H-bonding additives [16f] are significant further support the idea of a dipolar transition state.…”

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Highly regioselective decarboxylative Claisen rearrangement reactions of diallyl 2-sulfonylmalonates

Craig

Lansdell

Lewis

2007

Tetrahedron Letters

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The decarboxylative Claisen rearrangement of a range of substituted diallyl 2-sulfonylmalonates is described. The reaction displays a very high degree of regioselectivity, with allylic substituents possessing electron-rich substituents at the 3-position rearranging preferentially. The substrates are made by C-carboxylation of the corresponding allyl sulfonylacetates with allyl para-nitrophenyl carbonates. In one instance, the presence of a highly electron-withdrawing side-chain led to the competing formation of a γ-lactone by-product. The Claisen rearrangement continues to be the focus of considerable research effort. [1] Since its introduction in 1972, [2] the Ireland silyl ketene acetal variant in particular has been widely used in complex target-oriented synthesis. [3] This modified process benefits from the ease of preparation of the ketene acetal substrates and the relatively mild conditions for the sigmatropic rearrangement. In addition, it enables overall C-allylation of carboxylic acids using allylic alcohols as the surrogate electrophiles, with regiospecific allylic double-bond transposition. We recently reported [4,5] a novel variant of the Ireland-Claisen rearrangement reaction in which α-tosyl silyl keteneacetals formed in situ from allylic tosylacetates 1 in the presence of N,O-bis(trimethylsilyl)acetamide (BSA) and

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confidence: 99%

Highly regioselective decarboxylative Claisen rearrangement reactions of diallyl 2-sulfonylmalonates

Craig

Lansdell

Lewis

2007

Tetrahedron Letters

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“…Diesen Annahmen werden für die aliphatische Claisen-Umlagerung durch sekundäre kinetische Isotopeneffecte (Deuterium) bestätigt [43,44].…”

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Claisen‐Umlagerung im Rühr‐ und Durchflussbetrieb: Verständnis des Mechanismus und Steuerung der Einflussgrößen

Hessel

Shahbazali

Noël

et al. 2014

Chemie Ingenieur Technik

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Die Claisen-Umlagerung wurde in über 100 Jahren durch zahlreiche Forscher äußerst eingehend im Rührbetrieb untersucht. Insbesondere der Reaktionsmechanismus wurde in allen Details erforscht. Quantenmechanische Modellierung und moderne Kurzzeit-Spektroskopie haben hier ganz neue Impulse gegeben. Auch wurden schon erste Erfahrungen im Durchflussbetrieb in Mikroreaktoren gesammelt. Wie für viele andere Reaktionen so konnte eine massive Beschleunigung in neuen Prozessfenstern erreicht werden. Dieser Ü bersichtsartikel zeigt, dass das wahre Potenzial dennoch darauf wartet, für den Mikroreaktorbetrieb entdeckt zu werden.The Claisen rearrangement has been extensively studied over the past 100 years in batch mode. Especially the reaction mechanism has been determined in all details. Quantum-mechanical modelling and ultrashort pulse spectroscopy have recently provided entirely new insight. First experiments were carried out in microreactors using flow chemistry. An enhancement of the yield and selctivity in the new processing windows has been observed. This review shows, that the true and full potential has still not been fully explored for the microreactor processing.

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“…The development of the Claisen rearrangement (and variants thereof ) over the past century has unambiguously demonstrated the power and synthetic utility of this deceptively simple transformation. [1][2][3][4][5][6] While the regio-and stereoselective formation of new carbon-carbon bonds in this manner has been widely accepted to occur through a concerted, albeit asynchronous, [7][8][9][10] bond reorganization process via a sixmembered cyclic transition state, 11,12 many details about the reaction trajectory remain elusive (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Investigation of quantitative structure–reactivity relationships in the aliphatic Claisen rearrangement of bis-vinyl ethers reveals a dipolar, dissociative mechanism

O’Rourke

Wulff

2014

Org. Biomol. Chem.

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Kinetic investigations of substituent effects in the thermal rearrangement of bis-vinyl ether substrates are reported. Findings indicate that the influence of the various substituent patterns on the rate of rearrangement in these compounds differs from that documented in the literature for the analogous [3,3]-sigmatropic rearrangement of allyl vinyl ethers. In addition, the thermochemical data collected suggests the existence of a dissociative transition state with significant dipolar character. These findings provide a unique contribution to the already extensive body of literature dedicated to mechanistic investigation of the Claisen rearrangement of aliphatic allyl vinyl ethers.

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Secondary deuterium isotope effects and transition state structure in the aromatic Claisen rearrangement

Cited by 32 publications

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Highly regioselective decarboxylative Claisen rearrangement reactions of diallyl 2-sulfonylmalonates

Highly regioselective decarboxylative Claisen rearrangement reactions of diallyl 2-sulfonylmalonates

Claisen‐Umlagerung im Rühr‐ und Durchflussbetrieb: Verständnis des Mechanismus und Steuerung der Einflussgrößen

Investigation of quantitative structure–reactivity relationships in the aliphatic Claisen rearrangement of bis-vinyl ethers reveals a dipolar, dissociative mechanism

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