Neuere Methoden der präparativen organischen Chemie. 10. Synthesen mit Diazomethan

Eistert, Bernd

doi:10.1002/ange.19410540703

Cited by 38 publications

(2 citation statements)

References 44 publications

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“…The most significant results have probably been the ring enlargement of cyclic ketones with diazomethane and the Arndt-Eistert method for increasing thc chain length of carboxylic acids. These reactions are interpreted as involving nucleophilic attack of the diazoalkane at the carbonyl carbon, via diazonium and carbonium betaine intermediates [74]. However, a much older interpretation which postulates a 1,2,3-oxadiazoline (35) or even a 1,3,4-oxadiazoline (36) as an intermediate has never been refuted.…”

Section: C) Reactions With Hetero-multiple Bondsmentioning

confidence: 98%

1,3‐Dipolar Cycloadditions. Past and Future

Huisgen

1963

Angew. Chem. Int. Ed. Engl.

2,748

1,223

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Section: C) Reactions With Hetero-multiple Bondsmentioning

confidence: 98%

1,3‐Dipolar Cycloadditions. Past and Future

Huisgen

1963

Angew. Chem. Int. Ed. Engl.

2,748

1,223

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“…In contrast to the latter observation, the reaction of diphenyldiazomethane with dimethyl fumarate and maleate at 40°in a variety of solvents is reported to yield the 2pyrazoline derivative.26 Also, the rate of addition was not appreciably affected by the polarity of the solvent and this has been cited26 as evidence for the 1,3-dipolar addition mechanism rather than the stepwise zwitterion-ion intermediate. 30 If indeed, the reaction of diazoalkanes with olefins at high temperatures does proceed through the 1-pyrazoline as an intermediate, then another question arises. Does the 1-pyrazoline decompose to yield a diradical or an ionic intermediate?…”

Section: Resultsmentioning

confidence: 99%

Cyclopropanes. XIII. The Absolute Configuration of 1-Methyl-2,2-diphenylcyclopropane

Walborsky¹,

Pitt²

1962

J. Am. Chem. Soc.

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1-METHn-2,%DlPEENYLCYCLOPROPANE 4831It is the behavior in the acid solvents that is most striking. Catalysis by acid as found by Blomquist and FerrisI2 for t-butyl perbenzoate in several solvents containing trichloroacetic acid and as suggested by our experiment with heptafluorobutyric acid, is not apparent in most of the acids shown in Table IV. In acetic, ashloropropionic, propionic and n-butyric acids, the rates are not greatly different from those in chlorobenzene, and in the case of the last two are slightly lower. Although a-chloropropionic acid is a much stronger acid than acetic acid, the rate in it is smaller. Examination of the structures of these four acids suggested that their effects may be related to the number and strength of binding of the hydrogen atoms on the carbon atom alpha to the carboxylate group. This further suggested trying an acid with no hydrogen in the a-position, which explains the choice of a-chloroisobutyric acid.The great effect of the absence of hydrogen atoms on the a-carbon atom is shown by the more than fivefold increase in rate in a-chloroisobutyric acid above that in a-chloropropionic acid. When a mixture of 10 mole-per cent. of isobutyric acid and 90 mole-per cent. of a-chloroisobutyric acid was used as solvent with t-butyl permyristate a t llOo, the 105k value was 29.5 sec.-l, showing the inhibitory effect of the presence of the isobutyric acid.These results show that the acid catalysis expected of a carboxylic acid is diminished greatly if the acid has one or more hydrogen atoms on its cy-carbon atom. This stabilizing or inhibitory effect shows a dependence also upon the other atoms attached to the cy-carbon atom and in the (12) A. T. Blornquist and A. F. Ferris, J . A m . Chem. Soc., 73, 3412 (1951).case of propionic and butyric acids is great enough to render the net rate of decomposition of the perester lower than in pure chlorobenzene.Other evidence of combined inhibitory action and acid catalysis by carboxylic acids is found in the observations of Blomquist and Ferris12 with t-butyl perbenzoate. They found that the rate in acetic acid was higher than in aromatic solvents such as chlorobenzene a t the same temperature but that while addition of trichloroacetic acid to the ester in p-chlorotoluene had a marked catalytic effect, addition of dichloroacetic acid had practically no effect. An effect of the presence and the nature of the hydrogen atoms on the a-carbon of the acid is thus apparent in their work also.The exact nature of the action of carboxylic acids ;nust be determined by extensive further research and we do not wish to speculate upon it at present. No good clue to that nature is provided by the analysis of the products produced in n-butyric acid (Table VII) since that analysis is not sufficiently different from the one obtained for the decomposition in chlorobenzene. On the other hand, the effects of the acids on the AH* and AS* values (Table VI) do not fit well with the correlations found for peresters undergoing simple or "concerted" cleavage free of radi...

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The Reaction of Diazomethane and its Derivatives with Aldehydes and Ketones

Gutsche¹

2011

Organic Reactions

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Diazomethane and its derivatives react with aldehdyes and ketones usually under very mild conditions to yield a variety of interesting and often useful products. The reaction is most often carried out by either allowing the carbonyl compound to react with an ethereal solution of the diazomethane derivative with or without the addition of a catalyst, or by treating a methanol solution of the carbonyl compound with a nitrosoalkylurethane in the presence of a base, Only the reactions of diazomethane and its alkyl and aryl derivatives are discussed in detail.

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Neuere Methoden der präparativen organischen Chemie. 10. Synthesen mit Diazomethan

Cited by 38 publications

References 44 publications

1,3‐Dipolar Cycloadditions. Past and Future

1,3‐Dipolar Cycloadditions. Past and Future

Cyclopropanes. XIII. The Absolute Configuration of 1-Methyl-2,2-diphenylcyclopropane

The Reaction of Diazomethane and its Derivatives with Aldehydes and Ketones

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