Competitive kinetic processes in the thermal rearrangement of 1,1-difluoro-2-(dideuteriomethylene)-cyclopropane

Gautriaud, Emilie; Cai, Xiaohong

doi:10.1016/j.jfluchem.2004.12.004

Cited by 16 publications

(11 citation statements)

References 12 publications

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“…Dolbier et al investigated the thermal rearrangement at 180 8C of 1,1-difluoro-2-(dideuteriomethylene)-cyclopropane, which led to a mixture of three components constituted of the starting material, the reversible rearranged 1,1-difluoro-3,3-dideuterio-2-methylenecyclopropane, and the reversible rearranged 2,2-dideuterio-1-(difluoromethylene)-cyclopropane. [131] The observed experimental ratio of the two rate constants (2.3) was consistent with the strong preference of a CF 2 radical center for a pyramidal geometry.…”

Section: Rearrangementssupporting

confidence: 65%

Synthesis of Methylene‐ and Alkylidenecyclopropane Derivatives

Audran

Pellissier

2010

Adv Synth Catal

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Since the methylenecyclopropane moiety is found in many biologically active natural substances, the synthesis of methylene-and alkylidenecyclopropanes remains a considerable challenge. In addition, an attractive feature is their surprising stability, accompanied by a high level of strain, conferring on them an otherwise unattainable chemical reactivity. The growing interest in the chemistry of these compounds has in its turn stimulated the development of alternative approaches to their skeleton, aimed at selectively introducing structural and chemical diversification. The three principal methods to synthesize these important compounds are based on the formation of the cyclopropane ring, the use of preformed cyclopropanes, and the use of preformed methyleneand alkylidenecyclopropanes.

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Section: Rearrangementssupporting

confidence: 65%

Synthesis of Methylene‐ and Alkylidenecyclopropane Derivatives

Audran

Pellissier

2010

Adv Synth Catal

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“…Herein, we report the results of our study. We find that the presence of two CF 2 groups destabilizes the cyclopropane ring of 9, not only relative to the TS for ring opening, but also relative to the diradical intermediate (10) in the rearrangement and to the product formed (11). Consequently, as conjectured by Dolbier and co-workers, 12 the low E a for rearrangement of 9 is due to destabilizing interactions between the vicinal CF 2 groups in 9, rather than to stabilization of the TS by the presence of two CF 2 groups.…”

Section: Introductionmentioning

confidence: 87%

Ab Initio Calculations of the Potential Surface for Rearrangement of 2,2,3,3-Tetrafluoromethylenecyclopropane to 1-(Difluoromethylene)-2,2-difluorocyclopropane

2006

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(4/4)CASSCF and CASPT2 calculations have been performed to understand the reason that addition of a second pair of geminal fluorines to methylenecyclopropane lowers the barrier to rearrangement by 6.7 kcal/mol more than addition of the first pair. Our calculations duplicate this experimental finding by Dolbier and co-workers. Our computational results confirm Dolbier's conjecture, that the non-additive lowering of Ea for the rearrangement of 2,2,3,3-tetrafluoromethylenecyclopropane (9) to 1-(difluoromethylene)-2,2-difluorocyclopropane (11) is due to destabilization of 9 by the presence of the vicinal CF2 groups in this fluorocarbon. In the course of exploring the potential energy surface for the rearrangement of 9, we have located a bond-stretch isomer (20) that differs from 9 by inversion of both CF2 groups. The enthalpy of 20 is computed to be 21.9 kcal/mol higher than that of 9, but direct interconversion of these two "bond-stretch invertomers" requires passage over a TS whose enthalpy is calculated to be 11.7 kcal/mol higher than that of 20.

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“…Dolbier examined the rearrangement of 1,1-difluoro-2-methylenecyclopropane ( 96 ) ( Scheme 45 ) [ 92 ]. At 210 °C the rate of cleavage of the proximal bond was only 3.8 times faster than for the analogous hydrocarbon.…”

Section: Reviewmentioning

confidence: 99%

The preparation and properties of 1,1-difluorocyclopropane derivatives

Adekenova¹,

Wyatt²,

Адекенов³

2021

Beilstein J. Org. Chem.

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Recently, the functionalization of organic molecules with fluorine substituents has grown rapidly due to its applications in such fields as medicine, agriculture or materials sciences. The aim of this article is to review the importance of 1,1-difluorocyclopropane derivatives in synthesis. It will examine the role of the fluorine substituents in both ring-forming and ring-opening reactions, as well as methods for obtaining difluorocyclopropanes as single enantiomers. Several examples are provided to highlight the biological importance of this class of compounds.

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Competitive kinetic processes in the thermal rearrangement of 1,1-difluoro-2-(dideuteriomethylene)-cyclopropane

Cited by 16 publications

References 12 publications

Synthesis of Methylene‐ and Alkylidenecyclopropane Derivatives

Synthesis of Methylene‐ and Alkylidenecyclopropane Derivatives

Ab Initio Calculations of the Potential Surface for Rearrangement of 2,2,3,3-Tetrafluoromethylenecyclopropane to 1-(Difluoromethylene)-2,2-difluorocyclopropane

The preparation and properties of 1,1-difluorocyclopropane derivatives

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