Patent ID: 6893861

Claim:
A process for preparing 4,4,4-trifluoro-3(R)-hydroxybutyric acid derivatives of the formula wherein R 1 is (a) —OR 2 , in which R 2 is hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, C 3-8 -cycloalkyl, aryl, alkoxyalkyl or alkoxyalkoxyalkyl, (b) —NR 3 R 4 , in which R 3 and R 4 are identical or different and represent hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, C 3-8 -cycloalkyl or aryl, or (c) —SR 5 , in which R 5 is hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, aryl or C 3-8 -cycloalkyl, which process comprises: (i) reacting a trifluoroacetoacetic acid derivative of formula II wherein R 1 is (a) —OR 2 , in which R 2 is hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, C 3-8 -cycloalkyl, aryl, alkoxyalkyl or alkoxyalkoxyalkyl, (b) —NR 3 R 4 , in which R 3 and R 4 are identical or different and represent hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, C 3-8 -cycloalkyl or aryl, or (c) —SR 5 , in which R 5 is hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, aryl or C 3-8 -cycloalkyl, with a microorganism of the species Escherichia coli or cell-free extracts derived therefrom, wherein said microorganism is transformed with a gene encoding a NADPH generator or regenerator and wherein said microorganism expresses an NADPH-dependent enzyme having carbonyl reductase activity which enantioselectively reduces the trifluoroacetoacetic acid derivatives of formula II leading to the production of 4,4,4-trifluoro-3(R)-hydroxybutyric acid derivatives of the formula: wherein R 1 is (a) —OR 2 , in which R 2 is hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, C 3-8 -cycloalkyl, aryl, alkoxyalkyl or alkoxyalkoxyalkyl, (b) —NR 3 R 4 , in which R 3 and R 4 are identical or different and represent hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, C 3-8 -cycloalkyl or aryl, or (c) —SR 5 , in which R 5 is hydrogen, C 1-10 -alkyl, C 2-10 -alkenyl, aryl or C 3-8 -cycloalkyl; and (ii) isolating the 4,4,4-trifluoro-3(R)-hydroxybutyric acid derivatives produced.