Patent ID: 8212065

Claim:
A method for the production of compounds of the formula I: wherein a compound of the formula II, is reacted with R 4 MgX and ZnY 2 or R 4 MgX and ZnR 4 2 , with inversion of the stereoconfiguration at the α-carbonyl carbon atom, to give a compound according to formula I, in which R 1 is OM, O—R 5 or NR 5 R 6 , where M is a metal ion and R 5 and R 6 , independently of one another, represent a straight-chain or branched alkyl radical, alkenyl radical, arylalkyl radical, aryl radical or heteroaryl radical, in which R 2 is a sulphonate leaving group, phosphate leaving group, carboxylate leaving group, carbamate leaving group, carbonate leaving group or a halide, in which R 3 represents a straight-chain or branched alkyl radical, alkenyl radical, arylalkyl radical, aryl radical or heteroaryl radical which optionally has 5-7 carbon atoms and 1-2 hetero atoms, selected from O, N, P and S, as substituents or are interrupted by the hetero atoms, in which R 4 represents a straight-chain or branched alkyl radical, alkenyl radical, arylalkyl radical, arylradical or heteroaryl radical, in which, in R 1 to R 6 , an alkyl radical has 1-15 carbon atoms, an alkenyl radical 2-15 carbon atoms, an arylalkyl radical 5-15 carbon atoms, an aryl radical 5-10 carbon atoms and a heteroaryl radical 5-8 carbon atoms and 1-2 hetero atoms, selected from O, N, P and S, in which X represents a halogen and in which Y represents a sulphonate, a sulphate, a carboxylate, an alcoholate, a nitrate, a chalcogen or a halogen.