Reactions of 3,3,3-Trihalogeno-1-nitropropenes with Arenes in the Superacid CF3SO3H: Synthesis of ( Z)-3,3,3-Trihalogeno-1,2-diarylpropan-1-one Oximes and Study on the Reaction Mechanism

Andrei A Golushko; Maria A Sandzhieva; Alexander Yu Ivanov; Irina A Boyarskaya; Olesya V Khoroshilova; Alexey Yu Barkov; Aleksander V Vasilyev

doi:10.1021/acs.joc.8b01406

Reactions of 3,3,3-Trihalogeno-1-nitropropenes with Arenes in the Superacid CF₃SO₃H: Synthesis of ( Z)-3,3,3-Trihalogeno-1,2-diarylpropan-1-one Oximes and Study on the Reaction Mechanism

J Org Chem. 2018 Sep 7;83(17):10142-10157. doi: 10.1021/acs.joc.8b01406. Epub 2018 Jul 26.

Authors

Andrei A Golushko¹, Maria A Sandzhieva², Alexander Yu Ivanov³, Irina A Boyarskaya¹, Olesya V Khoroshilova⁴, Alexey Yu Barkov⁵, Aleksander V Vasilyev^{1

2}

Affiliations

¹ Department of Organic Chemistry, Institute of Chemistry , Saint Petersburg State University , Universitetskaya nab., 7/9 , Saint Petersburg , 199034 , Russia.
² Department of Chemistry , Saint Petersburg State Forest Technical University , Institutsky per., 5 , Saint Petersburg , 194021 , Russia.
³ Center for Magnetic Resonance, Research Park , St. Petersburg State University , Universitetskiy pr., 26 , Saint Petersburg , Petrodvoretz 198504 , Russia.
⁴ Center for X-ray Diffraction Studies, Research Park , St. Petersburg State University , Universitetskiy pr., 26 , Saint Petersburg , Petrodvoretz 198504 , Russia.
⁵ Institute of Natural Sciences and Mathematics , Ural Federal University , Mira str., 19 , Yekaterinburg , 620000 , Russia.

PMID: 30004232
DOI: 10.1021/acs.joc.8b01406

Abstract

3,3,3-Trihalogeno-1-nitropropenes C(Hal₃)CH═CH(NO₂) (Hal = F, Cl, Br) in reaction with arenes in the superacid CF₃SO₃H (TfOH) at room temperature in 1 h afford 3,3,3-trihalogeno-1,2-diarylpropan-1-one oximes C(Hal₃)CH(Ar)-C(Ar)═NOH (CHal₃-oximes) in yields of 23-99%. Such CHal₃-oximes having one ortho-substituent in the aryl ring exist as atropoisomers in solutions at room temperature. Several cationic intermediates of this reaction were studied by means of NMR and DFT calculations, which proves the detailed reaction mechanism of the formation of CHal₃-oximes in TfOH. CHal₃-oximes (for Hal = Cl, Br) with DBU in DMF at microwave or thermal activation are cyclized into 5-halogeno-3,4-diarylisoxazoles in yields of 37-59%. CHal₃-oximes under the conditions of Beckmann rearrangement with PCl₅ in benzene at room temperature in 24 h are turned at first into imidoyl chlorides (yields of 94-96%), which undergo transformation into the corresponding benzamides PhCONHCHPh(CHal₃) on silica gel (yields of 46-47%).