合成路线1

The intermediate 3-(3,4-dichlorophenyl)-3-buten-1-ol silyl ether (XII) was prepared by several procedures: 1) Addition of the organozinc reagent (IX) (generated from 1-bromo-3,4-dichlorobenzene (VIII)) to diketene (X) in the presence of palladium catalyst, followed by esterification with MeOH and H2SO4 furnished 3-arylbutenoate methyl ester (XI), which was reduced to alcohol with LiAlH4 and then silylated with tert-butyldimethylsilyl chloride to give silyl ether (XII). 2) In an alternative procedure, ethyl 3-(3,4-dichlorophenyl)-3-oxopropionate (XIII) was protected with triethyl orthoformate in the presence of p-toluenesulfonic acid and then reduced to alcohol (XIV) with LiAlH4. Ketal deprotection of (XIV) with trifluoroacetic acid provided hydroxy ketone (XV). After silylation of (XV) with tert-butyldimethylsilyl chloride, subsequent Wittig condensation with methylene triphenylphosphorane gave intermediate silyl eher (XII). 3) In a further procedure, the Grignard reagent (XVI) (generated from 1-bromo-3,4-dichlorobenzene (VIII)) was coupled with 3-iodo-3-buten-1-ol silyl ether (XVII) in the presence of palladium catalyst to furnish intermediate ether (XII).