A fluorinated analog of the 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) ligand was synthesized with OCF3-substitution of the aryl groups in BINAP skeleton (p-OCF3-BINAP). Ruthenium complexes of both BINAP (Ru-BINAP) and (p-OCF3)-BINAP (Ru-[(p-OCF3)BINAP]) were also synthesized and investigated as catalysts for hydrogenation of tiglic acid in methanol. Typically, Ru-[(p-OCF3)-BINAP] had lower activity but had higher enantioselectivity at high hydrogen pressures than Ru-BINAP at the same condition. The effect of OCF3 groups on the catalytic properties was discussed on the basis of NMR spectra and kinetic data. Ru-[(p-OCF3)-BINAP] was found to have sufficiently high solubility in dense CO2 for homogeneous catalytic reactions and was investigated for hydrogenation of tiglic acid in CO2. The results showed that CO2 had a great influence on both activity and enantioselectivity. Addition of methanol to CO2 was found to increase the enantioselectivity. (C) 2003 Published by Elsevier B.V.