Nucleophilic fluoroalkylation of iminium salts

Nucleophilic Trifluoromethylation of C=N Bonds

“…Salts 32 can be trifluoromethylated with TMSCF 3 in DMF in the presence of potassium fluoride or sodium acetate with the former activator affording slightly higher yields of products 33. [34] The efficient use of potassium fluoride is remarkable, since employment of this salt as a source of fluoride frequently requires harsh conditions. Scheme 29.…”

Trifluoromethylation of the amide group

“…NaBH 4 , BF 3 •OEt 2 , dioxane, 50 °C, 2 h; ii. BF 3 •OEt 2 , CH 2 Cl 2 , -25→20 °C, 1 h. 13 C NMR (75 MHz), δ: 22.1 (NCH 2 CH 2 ); 31.2 (CH 2 ); 35.7 (CH 2 ); 51.6 (CH 2 ); 52.2 (CH 2 ); 67.2 (q, CCF 3 , J = 23.8 Hz); 119.0 (H 2 C=); 126.8 (CH); 128.0 (CH); 128.2 (CH); 128.6 (q, CF 3 , J = 291.4 Hz); 132.8 (CH=CH 2 ); 140.2 (C i ). 19 13 …”

“…13 Here we propose to use a cation generated in the O alkylation of a car bamoyl group as an electrophile. 14, 15 Methylation of N benzylpyrrolidone (1) with methyl triflate in hot 1,2 dichloroethane produces cation A, which can be transformed into α methoxy α trifluoromethyl amine 2 by a reaction with Me 3 SiCF 3 and KF in DMF (Scheme 1).…”

“…It should be emphasized that compound 4c contains adjacent quaternary C atoms, which is evidence for the efficiency of this method of C-C bond formation. 1 H, 13 C, and 19 F NMR spectra were recorded on Bruker AM 300 and Bruker AC 200 instruments in CDCl 3 . Dichloro ethane and dichloromethane were distilled over CaH 2 immedi ately before use; DMF was distilled in vacuo over P 2 O 5 and kept over molecular sieves (4 Å).…”

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

“…Such transformations have been achieved using CH 2 (CF 3 )NR 2 as the iminium ion precursors [ 15 ], trifluoroacetaldehyde hemiaminals [ 16 – 18 ], N , O -acetals [ 19 ] and N , N -acetals [ 20 ], 2-(trifluoromethyl)-1,3-oxazolidines [ 21 ], and N -( tert -butylsulfinyl)trifluoroacetaldimine [ 11 , 22 ]. Other synthetic approaches to α-CF 3 -substituted amines include nucleophilic trifluoromethylation strategies [ 17 ], such as the reaction of trifluoroacetaldehyde hemiaminals with enolizable carbonyl compounds in the presence of a strong base [ 23 ], the reaction of aldiminium salts with (trifluoromethyl)trimethylsilane/Lewis base [ 24 ], and the preparation of secondary α-(trifluoromethyl)propargylamines from imines CF 3 CH=NR and lithium acetylides [ 25 ]. By a photoredox-catalytic process, primary α-(trifluoromethyl)-α-(4-pyridyl)benzylamines were obtained from α-(trifluoromethyl)-benzaldoximes and 4-cyanopyridine [ 26 ].…”