Scheme 4.

Synthesis of 3-(4-fluorophenyl)benzothiophene compounds with an ether linker^a

^aReagents and conditions: (a) N-bromoacetamide, DCM/EtOH, rt, 89%, 2 h; (b) H₂O₂, TFA, DCM, 0 °C, 2 h, 84%; (c) R₃OH, NaH, DMF, rt, 6 h, for 28a; Cs₂CO₃, DMF, 80 °C, overnight for 28b-d; (d) LiAlH₄, THF, 0 °C, 2 h; (e) BBr₃, DCM, −78 °C to rt, 4-48 h.