Jan Barten

Generation of heteroarylium-N-difluoromethylides and heteroaryl-N-difluoromethyl anions and their reactions with electrophiles: heteroaryl- and heteroarylium-N-difluoromethyl trimethylsilanes and a new heteroaryl-N-trifluoromethane

Abstract Reductive debromination of N -bromodifluoromethyl-4-dimethylaminopyridinium bromide, 1-bromodifluoromethyl-imidazole, 1-methyl-3-bromodifluoromethyl-imidazolium bromide and 1-bromodifluoromethyl-2-methyl-benzimidazole using tetrakis(dimethylamino)ethylene (TDAE) or tris(diethylamido)phosphite leads to new fluorinated carbanionic species, namely heteroarylium- N -difluoromethylides and heteroaryl- N -difluoromethyl anions. In the presence of electrophiles such as benzaldehyde, chlorodiphenylphosphine and chlorotrimethylsilane, the corresponding heteroarylium- and heteroaryl- N -difluoromethylated derivatives, imidazole- N -difluoromethyl-phosphines and -silanes, 2-methyl-benzimidazole- N -difluoromethyltrimethyl-carbinols-phosphines and -silanes were obtained. Similar 4-dimethylaminopyridinium derivatives were synthesized.

Simple access to novel β-hydroxy-β-trifluoromethyl imines

Abstract Selected imines reacted with three different trifluoromethyl group-containing ketones in a non-catalyzed manner at ambient temperature to give the corresponding β-hydroxy-β-trifluoromethyl imines in good to excellent yields. With 1,1,1-trifluoroacetone a 1:1 and a 2:1 reaction product was obtained. The reduction of 2-isopropylimino-4-phenyl-5,5,5-trifluoropentan-4-ol led to a 5:1 diastereomeric mixture of the corresponding amine, whose dominant form was found to be (2S, 4R) 4-isopropylamino-4-phenyl-2-trifluoromethyl-butan-2-ol in the solid state. Hydrolysis in one case gave the respective β-hydroxy ketone.

Novel and facile synthesis of fluorinated enamino ketones and amino alcohols

Selected imines and one bis-imine react via their enamine tautomers with terminal perfluorinated epoxides, e.g. hexafluoropropene oxide to produce fluorinated enamino ketones or imino ketones. In contrast, internal perfluorinated linear epoxides and one cyclic epoxide yield intermediate imino alcohols, which in one case added hexafluoroacetone, furnishing a new imino diol investigated by X-ray diffraction.