申请人:——
公开号:US20040077059A1
公开(公告)日:2004-04-22
Method for the preparation of an enantiomerically enriched ester, in which a mixture of the enantiomers of the corresponding secondary alcohol is subjected, in the presence of an acyl donor, to an enantioselective conversion in the presence of a racemisation catalyst upon which the ester is formed and an acyl donor residue is obtained, and in which the acyl donor residue is irreversibly removed from the phase in which the enantioselective conversion takes place. Preferably the enantioselective conversion is carried out enzymatically and a transfer hydrogenation catalyst is used as racemisation catalyst.
The secondary alcohol can be formed in situ from the corresponding ketone, in the presence of a hydrogen donor. It is also possible to use a mixture of the secondary alcohol and the corresponding ketone as substrate.
Preferably the acyl donor is chosen so that the acyl donor residue is converted in situ into another compound and/or the acyl donor residue is removed via distillation under reduced pressure.
The enantiomerically enriched esters obtained can subsequently be converted into the corresponding enantiomerically enriched alcohols, which are desirable intermediate products in the preparation of liquid crystals, agro chemicals or pharmaceuticals.
制备对映体富集酯的方法,在该方法中,相应仲醇的对映体混合物在酰基供体存在下,在消旋化催化剂存在下进行对映体选择性转化,在此过程中形成酯并获得酰基供体残留物,酰基供体残留物不可逆转地从进行对映体选择性转化的相中移除。最好用酶法进行对映选择性转化,并使用转移氢化催化剂作为消旋化催化剂。
在氢供体存在的情况下,仲醇可由相应的酮原位生成。也可以使用仲醇和相应酮的混合物作为底物。
最好选择酰基供体,以便酰基供体残留物就地转化为另一种化合物和/或通过减压蒸馏除去酰基供体残留物。
获得的对映体富集酯随后可转化为相应的对映体富集醇,这些醇是制备液晶、农用化学品或药物的理想中间产品。