At ambient temperature, to a stirred solution containing 3-isopropyl-4-methoxybenzoic acid (27.00 g, 0.139 mol, RN-33537-78-9) and oxalyl chloride (13.3 mL, 0.153 mol) in CH2Cl2 (460 mL) was added N,N-DMF (5 drops). After 2 h, the reaction was cooled to -78° C. To the reaction was added tin (IV) chloride (17.89 mL, 0.153 mol) followed by a solution of 2-benzyl-4,5-dimethylthiophene (28.12 g, 0.139 mol) in CH2Cl2 (120 mL) that had been previously cooled to -78° C. After the addition was complete, the dry ice/acetone bath was removed and the reaction was stirred for 18 h, eventually warming to ambient temperature. The reaction was quenched into H2O (2 L) and extracted with ether. The combined ethereal extracts were sequentially washed with 1N HCl (3×500 mL), H2O (2×500 mL), NaHCO3 (2×500 mL), brine (1×500 mL), dried (MgSO4) and concentrated. Purification on silica gel, eluting with 5% EtOAc/pet. ether, gave 43.65 g (83%) of the title compound as an oil. 1H NMR (DMSO-d6) δ 1.13 (s, 3 H), 1.15 (s, 3 H), 1.81 (s, 3 H), 2.26 (s, 3 H), 3.23 (q, 1 H), 3.85 (s, 2 H), 3.88 (s, 3 H), 7.04-7.24 (m, 6 H), 7.55 (dd, 1 H), 7.63 (d, 1 H).
