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[3+2] CYCLOADDITION REACTIONS OF 1-SUBSTITUTED 3,3,3-TRIFLUOROPROPENES WITH DIAZO COMPOUNDS AND NITRILIMINES – SYNTHESIS OF PYRAZOLINES AND PYRAZOLES

Юрий Н. Маркитанов, Вадим М. Тимошенко, Сергей С. Михайличенко, Эдуард Б. Русанов, Александр И. Хижан, Юрий Г. Шермолович
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Abstract


1,3-Dipolar cycloaddition reactions of 3,3,3-trifluoropropene derivatives containing a sulfonyl, sulfamide, or sulfoximine substituent in position 1 with diazomethane proceed with the formation of 3-substituted 4-(trifluoromethyl)-4,5-dihydro-1H-pyrazoles and 3(trifluoromethyl)-1H-pyrazole, whereas reactions with ethyl diazoacetate and 2,2,2-trifluorodiazoethane lead to the formation of isomeric 5(3)-substituted 4-trifluoromethyl-3,4(4,5)-dihydro-2(1)H-pyrazoles and 4-substituted 5-(trifluoromethyl)-4,5-dihydro-1H-pyrazoles, the stability of which depends on the nature of the heteroatomic substituent. The cycloaddition of 1-sulfonyl- and 1-sulfamoyl-substituted derivatives of 3,3,3-trifluoropropene to C-carbethoxy-N-phenylnitrilimine gives rise to 4-substituted ethyl 1-phenyl-5-(trifluoromethyl)-4,5-dihydro-1H-pyrazole-3-carboxylates and ethyl 1-phenyl-4-(trifluoromethyl)-1H-pyrazole-3-carboxylate.

 


Keywords


diazomethane; ethyl diazoacetate; nitrilimine; phosphonate; pyrazole; pyrazoline; sulfamide; sulfone; sulfoximine; 2,2,2-trifluorodiazoethane; trifluoromethyl group; cycloaddition.

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