A stirred suspension of 7-(2-fluoro-4-nitrophenoxy)-2-iodothieno[3,2-b]pyridine (24) [US 2006/0287343 A1] (5.00 g, 12.01 mmol, scheme 4)], 5-formyl-2-furanboronic acid (2.19 g, 15.19 mmol), Pd(PPh3)2Cl2 (422 mg, 0.6 mmol), Na2CO3 (8.53 g, 80.50 mmol) in a mixture of DME/ethanol/water (60 mL/40 mL/40 mL) was degassed with nitrogen for 15 min, and heated at 65° C. for five hours under nitrogen. The reaction mixture was allowed to cool to room temperature, and filtered. The cake was successively washed with water and AcOEt. The filtrate and washings were combined, extracted with AcOEt. The extract was successively washed with water, saturated solution of ammonium chloride, water and brine, and concentrated. The residue was combined with the cake, absorbed on silica gel and subjected to flash column chromatography on silica gel (eluents AcOEt/DCM: 10/90 to 20/90, then MeOH/DCM: 5/95) followed by trituration with AcOEt, to afford aldehyde 107 (3.886 g, 84% yield) as a pale clay solid. MS (m/z): 385.0 (M+H).
