[Cl:1][C:2]1[CH:7]=[CH:6][C:5](/[CH:8]=[CH:9]/B(O)O)=[CH:4][CH:3]=1.Br[C:14]1[C:18]([CH:19]=[O:20])=[CH:17][S:16][CH:15]=1.[O-]P([O-])([O-])=O.[K+].[K+].[K+].C(#N)C>O.CC([O-])=O.CC([O-])=O.[Pd+2]>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH:8]=[CH:9][C:14]2[C:18]([CH:19]=[O:20])=[CH:17][S:16][CH:15]=2)=[CH:4][CH:3]=1
To a 40-mL scintillation vial containing trans-2-(4-chlorophenyl)vinylboronic acid (0.42 g, 2.30 mmol), 3-bromo-4-formylthiophene (0.40 g, 2.09 mmol), K3PO4 (0.490 g, 2.30 mmol), TPP (22 mg, 0.08 mmol, 4 mol %), Pd(OAc)2 (4.7 mg, 0.02 mmol, 1 mol %) and a stir-bar, was added acetonitrile (2.5 mL). The vial was purged with N2, capped tightly and heated at 94° C. (aluminum multi-reaction block) while vigorously stirred for 32 h. The reaction was diluted with water and extracted with EtOAc (3×50 mL). The combined extracts were washed with brine, dried over Na2SO4, filtered and concentrated. Purification by flash chromatography (Isco CombiFlash) 0-10% EtOAc in heptane afforded the desired 4-[2-(4-chlorophenyl)-vinyl]-thiophene-3-carbaldehyde (285 mg, 54%). 1H NMR (400 MHz, CDCl3) δ ppm 6.99 (d, J=16.38 Hz, 1H), 7.31-7.36 (m, 2H), 7.45-7.49 (m, 2H), 7.50 (d, J=3.20 Hz, 1H), 7.76 (dd, J=16.34, 0.78 Hz, 1H), 8.13 (d, J=3.20 Hz, 1H), 10.07 (d, J=0.82 Hz, 1H).
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