Fig. 2: Synthetic route.

Reaction conditions: a Pd(PPh₃)₄, K₂CO₃, THF/H₂O, 110 °C, overnight; b SnCl₂, HCl, THF, r.t., 16 h, 12 % in two steps; c (CH₃)₂CO, NaHCO₃, Oxone, dichloromethane, H₂O, -5 °C, 24 h, 33%; d phenyl ether, 200 °C, 2 days, 37%-51%. Th Thiophene. oxTh thiophene-1,1-dioxide.