| abstract |
Process for reducing a compound of general structure III, wherein X is either hydrogen or OR 2 , and wherein R 1 and R 2 may be the same or different and represent hydrogen or a hydroxy protecting group, in an inert solvent with a reducing agent or with a reducing agent in the presence of a chiral auxiliary, to a mixture of compounds of general structure IVa and IVb, which is enriched in IVa, wherein X, R 1 , and R 2 are as defined above. |