合成路线1

In one method, metalation of 1-bromo-4-fluorobenzene (XI) with Mg in 2-MeTHF at 90 °C gives 4-fluorophenyl magnesium bromide (XII), which then couples with 2-bromothiophene (XIII) in the presence of NiCl2·dppe and AcOH in 2-MeTHF at 22 °C or in the presence of Pd(OAc)2 and DPPP in THF to yield 2-(4-fluorophenyl)thiophene (XIV). Finally, this compound undergoes Friedel–Crafts acylation with 5-iodo-2-methylbenzoic acid (XV) (initially chlorinated with SOCl2 in CH2Cl2) using AlCl3 in CH2Cl2, and subsequent reduction with (Me2SiH)2O in refluxing acetonitrile .
In another method, hydrolysis of methyl 5-bromo-2-methylbenzoate (XVI) with NaOH in MeOH at 50 °C gives rise to the benzoic acid (XVII) , which is then chlorinated with (COCl)2 in the presence of DMF in CH2Cl2 to yield 5-bromo-2-methylbenzoyl chloride (XVIII). Friedel–Crafts reaction of acyl chloride (XVIII) with 2-(4-fluorophenyl) thiophene (XIV) in the presence of AlCl3 in CH2Cl2 affords ketone (XIX), which is then reduced by means of Et3SiH and BF3·Et2O in CH2Cl2/acetonitrile to afford 2-(5-bromo-2-methylbenzoyl)-5-(4-fluorophenyl)thiophene (III) . Finally, compound (III) is iodinated with NaI and CuI in the presence of (MeNHCH2)2 in refluxing toluene/diglyme (IV) .
Alternatively, coupling of 4-fluorophenylboronic acid (XX) with either 2-bromothiophene (XIII) in the presence of PdCl2(PPh3)2 and Na2CO3 in dimethoxyethane at 75-80 °C or with 2-iodothiophene (XXI) in the presence of PdCl2(PPh3)2 at 50 °C affords 2-(4-fluorophenyl) thiophene (XIV) .