Patent ID: 8071796

Claim:
A process comprising reducing a compound of formula II in which at least one of the groups X 1 , X 2 , X 3 is fluoro, chloro, bromo, hydroxy, methoxy, ethoxy, trifluoromethyl or amino and the other groups X 1 , X 2 , X 3 are hydrogen, and in which at least one of the rows Z 1 , Z 2 , Z 3 is â€”Oâ€”, â€”Sâ€”, â€”NHâ€” or â€”N(â€”CH 3 )â€” and the other groups Z 1 , Z 2 , Z 3 are a â€”CH 2 â€” group, to obtain an enantiomerically pure compound according to formula I in which at least one of the groups X 1 , X 2 , X 3 is fluoro, chloro, bromo, hydroxy, methoxy, ethoxy, trifluoromethyl or amino and the other groups X 1 , X 2 , X 3 are hydrogen, and in which at least one of the groups Z 1 , Z 2 , Z 3 is â€”Oâ€”, â€”Sâ€”, â€”NHâ€”, or â€”N(â€”CH 3 )â€”, and the other groups Z 1 , Z 2 , Z 3 are a â€”CH 2 â€” group, wherein said compound of formula II is obtained by reacting a compound according to formula IV in which X 1 , X 2 , X 3 , Z 1 , Z 2 , Z 3 have the above described meanings with enantiomerically pure 2-hydroxy-4-methyl-2-(trifluormethyl)pentenoic acid