Reaction of 6-hydroxy-2(1H)-pyridone with diazomethane. Isolation of a novel product

Nesnow, Stephen; Shapiro, R. N.

doi:10.1021/jo01258a122

Cited by 10 publications

(1 citation statement)

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“…Azo couplings of CH acidic compounds have also been observed with the parent diazomethane under neutral conditions, [28] which has been suggested to proceed via protonation of diazomethane and attack of the resulting methyldiazonium ion at the simultaneously formed carbanion [28b–d] . Analogous reactions of diazonium ions are known as Japp‐Klingemann reactions [29]…”

Section: Resultsmentioning

confidence: 99%

Quantification of the Electrophilicities of Diazoalkanes: Kinetics and Mechanism of Azo Couplings with Enamines and Sulfonium Ylides

Mayer

Stephenson

et al. 2022

Chemistry A European J

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Kinetics and mechanism of the reactions of methyl diazoacetate, dimethyl diazomalonate, 4-nitrophenyldiazomethane, and diphenyldiazomethane with sulfonium ylides and enamines were investigated by UV-Vis and NMR spectroscopy. Ordinary alkenes undergo 1,3-dipolar cycloadditions with these diazo compounds. In contrast, sulfonium ylides and enamines attack at the terminal nitrogen of the diazo alkanes to give zwitterions, which undergo various subsequent reactions. As only one new bond is formed in the ratedetermining step of these reactions, the correlation lg k 2 (20 °C) = s N (N + E) could be used to determine the onebond electrophilicities E of the diazo compounds from the measured second-order rate constants and the known reactivity indices N and s N of the sulfonium ylides and enamines. The resulting electrophilicity parameters (À 21 < E < À 18), which are 11-14 orders of magnitude smaller than that of the benzenediazonium ion, are used to define the scope of one-bond nucleophiles which may react with these diazoalkanes.

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Section: Resultsmentioning

confidence: 99%