| abstract |
The present invention provides for the preparation of these intermediates by asymmetric hydrogenation or microbiological or enzymatic reduction reactions with optically active heteroaromatic β-hydroxy esters of the general formula (I), chiral metal catalysts, useful for the synthesis of epothilone derivatives Β-ketoesters of the general formula (IV) used below, and methods for their preparation.n n n <Formula I>n n n n n n n n <Formula IV>n n n n n n n n In the formula,n n n A is a chemical formula Cyclic heteroaromatic moiety of wherein “heteroaromatic” has up to 2 heteroatoms selected from oxygen, nitrogen or sulfur, and 1 or selected from alkyl, optionally protected hydroxyalkyl, halo-alkyl, halogen or CN A 5- or 6-membered heteroaromatic ring optionally substituted with two substituents,n n n R is a straight or branched, optionally saturated alkyl chain, optionally containing one to three oxygen atoms; Phenyl; Cyclohexyl; Or benzyl residues. |