Preparation of methyl-2-(ω-iodoalkyl)propenoates and a facile route to 2-carbomethoxy-1,3-butadiene

Alanine, Alex I.D.; Fishwick, Colin W. G.; Jones, A. D.; Mitchell, Michael B.

doi:10.1016/s0040-4039(01)93823-7

Cited by 5 publications

(2 citation statements)

References 5 publications

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“…The facile dimerisation of 2-methoxycarbonylbuta-1,3-diene (2-MCBD) 1 to give dimethyl mikanecate 4 has been known for some time (Scheme 1). [1][2][3][4][5][6] Although the unusual ease with which this [4 ϩ 2]-cycloaddition takes place has been noted, a rationalisation of this phenomenon has yet to be offered. A communication by Jung and Zimmerman provided the first kinetic data on this dimerisation.…”

Section: Introductionmentioning

confidence: 99%

The dimerisation of 2-methoxycarbonylbuta-1,3-diene: the importance of paralocalisation energy in assessing diene reactivity

Spino¹,

Crawford²,

Cui³

et al. 1998

J. Chem. Soc., Perkin Trans. 2

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The dimerisation and competitive cycloaddition of 2-methoxycarbonylbuta-1,3-diene with electron-rich dienes has been investigated. Experimental results provide evidence that the enthalpy of the -system significantly influences the energy of the transition state of cycloadditions of this type. This has been corroborated by ab initio calculations. We propose an early reorganisation of the -electrons in such cycloadditions to explain the influence stated above.

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Section: Introductionmentioning

confidence: 99%

The dimerisation of 2-methoxycarbonylbuta-1,3-diene: the importance of paralocalisation energy in assessing diene reactivity

Spino¹,

Crawford²,

Cui³

et al. 1998

J. Chem. Soc., Perkin Trans. 2

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“…Ester substituted butadienes have attracted interest for use in cycloaddition reactions for the synthesis of terpenes. [4] To circumvent this problem, 2-carbomethoxy-1, 3-butadiene is generated in situ by dehydrohalogentation of methyl 2-(iodomethyl) propenoate, [5] by flash vacuum pyrrolysis of methyl 2-(methoxymethyl)-3-butenoate [6] or 3-carbomethoxypropynyl ethenyl ether [7] or by extrusion of sulfur dioxide from 3-carbomethoxy-3-sulfolene (i.e., the dimethyl ester of 2,5-dihydrothiophene-1,1-dioxide-3-carboxylic acid). It reacts almost exclusively with electron-deficient dienophiles, such as methyl vinyl ketone, maleic anhydride, and acrylates to form the corresponding cycloadducts.…”

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confidence: 99%

The One-Pot Synthesis and Diels-Alder Reactivity of 2,5-Dihydrothiophene- 1,1-dioxide-3-carboxylic Acid

Andrade

Berkner

Liotta

et al. 2003

Synthetic Communications

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A one-pot preparation of 2,5-dihydrothiophene-1,1-dioxide-3carboxylic acid (3-sulfolene-3-carboxylic acid) is reported. The carboxylation of 3-sulfolene, exclusively at the 3-position, using CO 2 and DBU proceeds to >90% conversion. A rapid workup gives 3-sulfolene-3-carboxylic acid, a stable precursor to 1,3-butadiene-2-carboxylic acid. High conversions to Diels-Alder adducts were obtained upon treatment of 3-sulfolene-3-carboxylic acid with various dienophiles.

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[2,3]1‐Thia‐Wittig Rearrangements Proceeding with Complete Inversion or with Partial Loss of Configuration at the Carbanionic Center

Brickmann

Brückner

1993

Chem. Ber.

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Two pairs of diastereomeric y-(benzy1oxy)-w(tributylstanny1) sulfides (anti-and syn-13, anti-and syn-30) were prepared. nBuLi induced tinllithium exchange in each of these compounds furnished a-lithiated sulfides which underwent [2,3]-thia-Wittig rearrangements in THF at -78°C within 30 min.Competing [1,2]-thia-Wittig rearrangements were not observed, not even starting from stannyl sulfides 30 where the \2,3) shift requires the intermediacy of lithium thiolates 32 in which the aromaticity of a benzene ring is given up. The homoally1 thiols syn-and anti-19 were formed stereoselectively starting from the allylthio stannanes anti-and syn-13, respectively. This implies that the underlying thia-Wittig rearrangements are stereospecific and proceed with inversion of configuration at the carbanionic center, and that the lithio sulfides anti-and syn-18 formed in the course of these reactions are configurationally stable until they rearrange. The benzylthio stannanes anti-and syn-30 rearranged with low stereoselectivity. They furnished the benzyl thiols 33 as 71:29 and 28: 72 mixtures of diastereomers, respectively. This means that the lithio sulfide intermediates involved in the latter rearrangements suffer some epimerization anti-31 + syn-31 prior to the sigmatropic bond shift.a-Hetero-substituted organolithium compounds are important tools in organic synthesis"]. Their carbanionic center is usually pyramidalized and often part of a C-Li bond ['].In a-hetero-substituted organolithium compounds 1 (R + H) which contain four dqferent ligands at the carbanionic center, the latter becomes a stereogenic center (,,stereocenter"). Accordingly, the organolithium compounds 1 a and 1 b with opposite configurations at the carbanionic centers are stereoisomers, i.e., enantiomers, if R is achiral, or diastereomers, if R is chiral. These isomers can interconvert under appropriate conditions by inversion of configuration at the lithium bearing stereocenter in an equilibrium reaction 1 a % 1 b. Therefore, in order to convert stereoselectively -through reaction with an electrophile E+-one isomer In the present study we probed the configurational stability of cl-lithio sulfides 1 (Het = S) on the time scale of [2,3]-thia-Wittig rearrangements 9 + 10. While the lack of configurational stability of lithio sulfides with respect to the rate of an intermolecular attack of several electrophiles (4[@; 5@]; 6[']; 7"') was documented repeatedly (Table 1, lower Chem.

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Preparation of methyl-2-(ω-iodoalkyl)propenoates and a facile route to 2-carbomethoxy-1,3-butadiene

Cited by 5 publications

References 5 publications

The dimerisation of 2-methoxycarbonylbuta-1,3-diene: the importance of paralocalisation energy in assessing diene reactivity

The dimerisation of 2-methoxycarbonylbuta-1,3-diene: the importance of paralocalisation energy in assessing diene reactivity

The One-Pot Synthesis and Diels-Alder Reactivity of 2,5-Dihydrothiophene- 1,1-dioxide-3-carboxylic Acid

[2,3]1‐Thia‐Wittig Rearrangements Proceeding with Complete Inversion or with Partial Loss of Configuration at the Carbanionic Center

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