摘要 |
<p>The invention relates to a process for producing a compound of formula (I) wherein R1, R2 and R3 are as defined in the specification, which comprises reacting a lactone with an imine to obtain a chiral diol of formula (IV) oxidizing the diol, condensing the resultant aldehyde with an enolether, hydrogenating the product, and chirally catalytically reducing the resultant ketone.</p> |