Development of a safely handleable synthetic equivalent of cyanonitrile oxide by 1,3-dipolar cycloaddition of nitroacetonitrile

Nishiwaki, Nagatoshi; Kumegawa, Yuta; Iwai, Kento; Yokoyama, Saichiro

doi:10.1039/c9cc03875b

Cited by 6 publications

(2 citation statements)

References 30 publications

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“…The nitronic acid tautomer of NAN is a 1,3-dipole and can therefore undergo cycloaddition upon heating with dipolarophiles, such as alkynes 61 , under acidic conditions to afford 3-cyanoisoxazoles 62 (Scheme ). Methacrylic acid 63 can be used as a dipolarophile without any modification, resulting in the formation of cyanoisoxazoline-5-carboxylic acid 64 . Products 62 and 64 are the same as cycloadducts as those obtained from the analogous reaction with nitrile oxide 58 ; thus, NAN serves as a synthetic equivalent of cyanonitrile oxide 58 .…”

Section: Cyanonitrile Oxidementioning

confidence: 99%

Nitroacetonitrile and Its Synthetic Equivalents

Iwai

Nishiwaki

2021

J. Org. Chem.

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Nitroacetonitrile (NAN) serves as a cyano(nitro)methylating agent facilitating the construction of polyfunctionalized compounds; however, its explosive property is a significant drawback in terms of practical handling. Alkali metal salts of NAN are thermally stable, but their insolubility in organic solvents restricts their use as a synthetic reagents. On the contrary, dipyrrolidinium cyano-aci-nitroacetate is soluble in common organic solvents and thermally stable, allowing for its use as an alternative synthetic equivalent of nitroacetonitrile for the construction of polyfunctionalized frameworks via cyano(nitro)methylation.

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Section: Cyanonitrile Oxidementioning

confidence: 99%

Nitroacetonitrile and Its Synthetic Equivalents

Iwai

Nishiwaki

2021

J. Org. Chem.

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“…Direct S N 2 substitution is also sometimes observed [ 7 ], in which a nitrite ion is eliminated. The high acidity of an α-proton of the nitro group easily generates a nitronate, which possesses both nucleophilic [ 8 , 9 ] and electrophilic sites to serve as a 1,3-dipole [ 10 , 11 ]. Moreover, the nitro group is a precursor of amino and carbonyl groups by reduction and Nef-type reactions [ 12 ], respectively.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Substituting Ability of Nitronate versus Enolate for Direct Substitution of a Nitro Group

2020

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α-Nitrocinnamate underwent the conjugate addition of an active methylene compound such as nitroacetate, 1,3-dicarbonyl compound, or α-nitroketone, and the following ring closure afforded functionalized heterocyclic frameworks. The reaction of cinnamate with nitroacetate occurs via nucleophilic substitution of a nitro group by the O-attack of the nitronate, which results in isoxazoline N-oxide. This protocol was applicable to 1,3-dicarbonyl compounds to afford dihydrofuran derivatives, including those derived from direct substitution of a nitro group caused by O-attack of enolate. It was found the reactivity was lowered by an electron-withdrawing group on the carbonyl moiety. When α-nitroketone was employed as a substrate, three kinds of products were possibly formed; of these, only isoxazoline N-oxide was identified. This result indicates that the substituting ability of nitronate is higher than that of enolate for the direct SN2 substitution of a nitro group.

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