Highly efficient synthesis of chiral α-CF3 amines via Rh-catalyzed asymmetric hydrogenation
Highly enantioselective catalytic asymmetric hydrogenation of α-CF3-enamides has been achieved by employing rhodium-DuanPhos as the catalyst, which provides a readily accessible method for the synthesis of chiral trifluoromethylated amines. The reaction has a broad substrate scope; both aryl- and alkyl-substituted α-CF3-enamides worked smoothly and afford the corresponding chiral amines in high yields and excellent enantioselectivities (up to 99% ee).
Jiang, Jun,Lu, Wenxin,Lv, Hui,Zhang, Xumu
supporting information
p. 1154 - 1156
(2015/03/14)
Exalted resonance demands in the substituent effects on the acetolyses of 2-arylethyl trifluoromethanesulfonates destabilized by cn and cf3 groups
Substituent effects on the acetolysis rates of 2-aryl-l-cyano-l- (trifluoromethyl)ethyl trifluoromethanesulfonates (α-OTf) and 2-aryl-2-cyano-2-(trifluoromethyl)ethyl trifluoromethanesulfonates (ss-OTf) were investigated by using LArSR equation. The obtained p and r+ values were p = -3.28, r+ = 0.98 and p = -3.48,r+ = 0.93 for the acetolysis of α-OTf and ss-OΥi, respectively. The obtained p values are comparable to those for typical aryl-assisted solvolyses, but the r+ values are much larger. The large r+ values suggest that the ester bond cleavages in the deactivated aryl-assisted solvolyses are assisted by the strong participation of the ss-aryl group.