Imines, fluorinated

Trifluoromethylisocyanide reacts with hydrogen fluoride to give a mixture of isomeric fluorinated imines [56] (equation 12)... 

Carbon-nitrogen multiple bonds in fluorinated imines and nitriles react with halogen fluoride reagents Imines provide 7V-chloroamine.s on reaction with chlo rme fluoride [62, 121, 122, 123] (equations 23 and 24) or with cesium fluoride and chlorine [124] and A -bromoammes on reaction with cesium fluoride and bromine (equation 24)... 

Racemic fluorinated tryptophan derivatives 31 were obtained from 3-methylene indole 29 and fluorinated imines 30 using the imino-ene reaction (Equation (18)).28 The highest yields were obtained for the more electrophilic imines (R2 = SC>2Ph, Ts, SC Me). Moreover, these reactions took place at ambient temperature. 

X-ray crystallographic analysis for 18 [15]. The fluorinated imines 16, 17, and 18 provided (S, S) amines (20) exclusively on reduction with NaBH4, where hydride attacked from the less hindered face via the preferred conformation 19. Regioselective Pd-catalyzed hydrogenolysis of 20 afforded enantiomerically pure 2-fluoro-, 2,2-difluoro-, and 2,2,2-trifluoro -1 -phenylethylamines [16]. 

Other reagents found capable of oxidizing highly fluorinated imines were chlorine... 

Reactive ketenes (usually generated in situ by treating an appropriate acyl chloride with a base) undergo the [2 + 2] cycloaddition with fluorinated imine to afford the mixture of stereoisomers of p-lactam 67 (Scheme 2.31). Then the kinetic optical resolution is performed on the product to obtain pure enantiomers. 

The synthesis of 2-arylpyrimidines carrying fluoroalkyl groups in 4- and 6-position can be achieved through base-catalyzed condensation of fluorinated imines 38, 40, and 43 with the corresponding aromatic aldehydes 44 (Fig. 7.13). ... 

Fustero et al. noticed that fluorinated imines lOg-h had received little attention so far in literature. In particular, the synthesis of the corresponding anti-Mannich adducts had never been explored previously. By employing Jprgensen s diphenyl-prolinol derivative 41, highly enantioselective one-pot reactions between aldehydes 2 and the fluoroaldimines lOg-h were conducted [31], leading to the fluorinated P-aUcyl-y-amino alcohols 42a-e in a highly selective anh-manner (Scheme 5.23). 

Wang W Li YL, Wang XS (2012) Highly efficient synthesis of 7-aryl-pyrano[3,4-c] pyrazolo[4,3-f]quinoline derivatives catalyzed by iodine. ARKIVOC vi 214-221 Lin XF, Cui SL, Wang YG (2006) Molecular iodine catalyzed one-pot synthesis of substituted quinolines from imines and aldehydes. Tetrahedron Lett 47 3127-3130 Jin G, Zhao J, Han J, Zhu S, Zhang J (2010) Iodine-promoted imino-Diels-Alder reaction of fluorinated imine with enol ether synthesis of 2-perfluorophenyl tetrahydroquinoline derivatives. Tetrahedron 66 913-917... 

Wang and co-workers developed an elegant catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides with low reactive fluorinated imines as the dipolarophiles catalyzed by Cu(MeCN)4BF4/PPFOMe complex for the synthesis of 2,4-frans-fluorinated imidazolidines (Scheme 25) [45]. This catalytic system exhibited high reactivity, excellent stereoselectivity, and broad substrate scope. 

Scheme 25 As3Trmietric [3+2] cycloaddition of azomethine ylides with fluorinated imines...

Xie H, Zhu J, ChenZ, Li S, Wu Y (2010) Diastereoselective silver-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with fluorinated imine. J Oig Chem 75 7468-7471... 

In summary, lithium alkyl aryl sulfoxides can be efficiently used as equivalents of chiral a-hydroxy alkyl carbanion in the synthesis of 3-fiuoroalkyl 3-amino alcohols. On the other hand, fluorinated imines are versatile and readily available electrophilic sources of fluoroalkyl/fluoroaiyl amino groups. Excellent stereocontrol and reactivity can be achieved using aldimines A-protected with a PM group, which also makes fluorinated aldimines electronrich enough to be easy to handle. Furthermore, the PMP group can be cleaved readily and under mild conditions, thus representing the... 

---