Asymmetric hydrogenation of 3,5-di-(trifluoromethyl)-acetophenone (1) to 1-[3,5-di-(trifluoromethyl)-phenyl]ethanol (2) was studied over 5 wt.% Rh/Al2O3 modified by cinchonidine (CD) and its O-methyl, O-ethyl, O-phenyl, O-trimethylsilyl, N-methyl, and N-benzyl derivatives. Replacement of CD by the ether derivatives resulted in the inversion of enantioselectivity from (S)-2 to (R)-2, and an improvement in chemoselectivity up to 100%. Interestingly, O-phenyl-CD (36% enantiomeric excess (ee)) is a more effective chiral modifier for the reaction than CD (27% ee). CD and its ether derivatives induced a small rate acceleration compared to the unmodified reaction. The basic quinuclidine N of CD seems to be a necessary prerequisite for enantioselection, whereas the role of the OH group is not clear yet. Blocking of the OH group changes the absolute configuration of the major enantiomer. (C) 2003 Elsevier B.V. All rights reserved.