| 摘要 |
The present invention relates to a process for the preparation of a compound of formula (I) comprising the steps of a) reacting a compound of formula (II) with a silylating or an acylating agent to produce compound of formula (III), wherein P1 is a protecting group selected from R2-Si-R3R4 or R1CO-, R1 is a group selected from C1-6alkyl or C3-6cycloalkyl, each group being optionally substituted by one or more substituents independently selected from fluoro or C1-4alkyl; R2, R3 and R4 are each independently a group selected from C1-6alkyl or phenyl, each group being optionally substituted by one or more substituents independently selected from fluoro or C1-4alkyl; b) halogenation or sulfinylation of the compound of formula (III) to produce a compound of formula (IV); wherein X is halo, or -O-SO-R5, and R5 is a group selected from C6-10aryl or heteroaryl, each group being optionally substituted by one or more substituents independently selected from chloro or C1-4alkyl; c) dehalogenation or desulfinylation of the compound of formula (IV) to produce compound of formula (V); and d) reacting the compound of formula (V) with a reducing agent to produce compound of formula (I). |
