Wydział Chemii

Nurbey Gulia

Jarosław Fornalski

Adrianna Gumienna

Małgorzata Ambroziak

Sławomir Szafert

2022

Chemistry-A European Journal

28

e202202449/1-e202202449/7

10.1002/chem.202202449

Naukowa

Angielski

Artykuł

A method of palladium-catalyzed C−H arylation assisted with a 3,4,4-trimethylpyrazol-5-on directing group, selectively providing mono- and di-ortho-arylated products is reported. Steric hindrance appearing between the directing group and the already introduced aryl substituent enables control of mono- vs. diarylation selectivity by the temperature of the reaction. Taking advantage of this, a series of monosubstituted and disubstituted derivatives were obtained in good yields. Moreover, unsymmetrical double-arylation in a one-pot procedure was developed to give corresponding products in reasonable yields. Additionally, synthesis and X-ray study of intermediate palladium metallacycles of both, the first and second arylation reactions, were conducted. X-ray structure comparison emphasizes the geometrical differences that were consistent with the observed reactivity. Finally, decarboxylative cleavage of the pyrazolone directing group under mild conditions gave synthetically useful hydrazones. The presented solution opens the alternative synthetic way to such ortho arylated derivatives of arylhydrazines.

arynes, C-H activation, homogeneous catalysis, hydrazones, palladium

http://dx.doi.org/10.1002/chem.202202449

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