| 摘要 |
A process is provided for the preparation of compounds of formula (I) herein comprising reacting a compound of formula (II), (III) or (IV) in the presence of <->OR and a hydroxide trapping agent or in the case of compounds of formula (IV) reacting in the presence of an auxiliary base and a hydroxide trapping agent (i.e. <->OR is substituted by the auxiliary base), wherein X is a leaving group and R<1> to R<4> are as defined above. |
