Syntheses of 2-(2,2,2-trifluoroethylidene)/(2,2-difluoroethyl)-1,3-dicarbonyl compounds and their fungicidal activities?

Organic Chemistry Frontiers Pub Date: 2018-12-07 DOI: 10.1039/C8QO01118D

Abstract

A Knoevenagel-type reaction of 1,3-diketone substrates with trifluoroacetic anhydride is described. The electrophilic species of trifluoroacetaldehyde is easily generated in situ by the reaction of trifluoroacetic anhydride/difluoroacetic anhydride with triethylamine. By this efficient and simple approach, a library of 2-(2,2,2-trifluoroethylidene)-1,3-dicarbonyl compounds that contain a wide range of functional groups were synthesized in good yields. Moreover, the reaction with difluoroacetic anhydride affords the corresponding (2,2-difluoroethyl)-1,3-dicarbonyls. Some of these compounds exhibited promising fungicidal activities.

Graphical abstract: Syntheses of 2-(2,2,2-trifluoroethylidene)/(2,2-difluoroethyl)-1,3-dicarbonyl compounds and their fungicidal activities
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