Heinz G. Viehe

Trifluoromethylated Heterocycles From Beta-trifluoroacetyl-lactams and Beta-trifluorobenzolactams

Trifluoromethyl substituted heterocycles have been prepared by condensation of the new beta-trifluoroacetyl-lactams 1 and -benzolactams 2 with methylhydrazine and benzamidine as bis-nucleophiles without opening of the lactam structure.

Trifluoromethylation of aliphatic halogen compounds

Aryl, heteroaryl or vinyl halides can be trifluoromethylated using CF3CO2Na-Cul. With alkyl iodides, however, the method fails, yielding trifluoroacetyl esters instead. Allylic halogens can be substituted with Burtons reagent, obtained from dihalogenodifluoromethane via CF3CdHal and transmetallation with Cul. A new access to trifluoropropionic acid is thereby found. Prop-2-ynyl bromide produces trifluoromethylallene. Attempts at trifluoromethylation of bromoacetate with CF3CO2Na-Cul in NMP (N-methyl-2-pyrrolidone) solution led to formation of the trifluoroacetoxy derivative and of a formal adduct of hexafluoroacetone to the alpha-position of NMP.

Cumulogy Supported By X-ray-analysis of 1,1-bis(dimethylamino)-4,4-dicyanobutatriene

The new title compound 7 and its corresponding diene 4 are the cumulogue and vinylogue of known 1,1-bis N,N-dimethylaminomethylenemalononitrile 8, respectively. These compounds 4 and 7 are crystalline with dipolar character and show exceptionally short central bonds.

2-Phenylthio-3,3,3-trifluoropropene, its sulfoxide and sulfone: Synthesis and reactivity in 1,3-dipolar cycloadditions.

Derivatives of 3,3,3-trifluoropropene 1 : alpha-sulfide 2, sulfoxide 3, sulfone 4 and bromide 6 are useful trifluoromethylated synthons. On reaction with diazo compounds, these derivatives can afford trifluoromethyl substituted pyrazolines, pyrazoles, cyclopropanes or allylsulfones in fair to excellent yields. 1,3-Dipolar cycloaddition of trifluoropropene derivatives 2-4 with N-benzylazomethine ylide provides disubstituted 3-trifluoromethyl-pyrrolidines.

Trifluoromethylated Pyrimidines Starting From Beta-trifluoroacetyl-lactams, Beta-trifluoroacetyl-lactone and Beta-trifluoroacetyl-cyclanone

A synthesis of trifluoromethylated pyrimidines from beta-trifluoroacetyl-lactams and -benzolactams is accomplished by reaction with benzamidine as bis-nucleophile. This condensation is also extended to cyclic trifluoromethylated 1,3-diketones and 3-aroyl-2-pyrrolidinones.

Diastereoselective 1,3-dipolar cycloadditions of new azomethine ylides derived from trifluorothioacetamides or cyanothioformamides

Deprotonation of trifluoromethyl or cyano thioamidium salts generates new azomethine ylides which undergo cycloaddition to dipolarophiles with high diastereoselectivity. Epimerisation, hydrolysis and reduction of the new trifluoromethylated heterocycles are also described

α- or β-trifluoromethyl epoxysulfones: New C3 reagents for heterocyclisation

Abstract The syntheses of α- and β-trifluoromethyl epoxysulfones 1 and 2 are described. Compound 1 reacts with nucleophiles and bis-nucleophiles to furnish trifluoromethyl ketones and trifluoromethyl heterocycles in good yield, while its isomer 2 leads to the opposite thiazole regioisomers with thioamides.

Diastereoselective cycloadditions of new trifluoromethyl azomethine ylides derived from trifluorothioacetamides

Two methods of generation of new trifluoromethyl azomethine ylides are described: by heating N,N-dimethyl-bis(methylthio)-orthotrifluoroacetamide 2 or by deprotonation of trifluoromethyl thioamidium salts. Trapping by dipolarophiles leads to 2-trifluoromethyl pyrrolidines and pyrrolizidines with high diastereoselectivity. Copyright (C) 1996 Published by Elsevier Science Ltd

Heterocyclization of 3-trifluoroacetyllactams By Hydrazines

3-Trifluoroacetyllactams may heterocyclize with hydrazine or with its methyl or phenyl derivative either without ring opening to annelated trifluoromethylpyrazoles or by Ring Opening - Ring Closure (RORC) reaction to zwitterionic salts of 4-omega-alkylamino-5-hydroxy-3-trifluoromethylpyrazoles.

Trifluoroethylidenation of compounds with activated methylene groups

Alpha-trifluoromethyl iminium trifluoroacetates 5 can be prepared from N-oxides 4 and used in situ or after isolation. Condensation occurs with carbonyl activated methylene groups to give useful beta-trifluoromethyl vinyl ketones 8.