Enantio selective hydrogenation of isopropyl-4,4,4-trifluoroacetoacetate in a continuous flow reactor Original Research Article

The study aimed at clarifying the feasibility of the synthesis of a chiral trifluoromethyl alcohol by continuous hydrogenation over Pt/Al2O3. The transformation of isopropyl-4,4,4-trifluoroacetoacetate to the corresponding β-hydroxyester was studied in a fixed bed reactor under differential reactor conditions. The chiral modifier and trifluoroacetic acid additive were continuously fed into the reactor in tetrahydrofuran solvent. The actual chiral modifier of Pt was an O-methyl-cinchonidine–trifluoroacetic acid ion-pair. Up to around 90% enantio selectivity (ee) and a turn over frequency (TOF) value of 810 h−1 were achieved by varying the pressure, temperature, total liquid flow rate and feed composition.