Synthesis
General procedure for the synthesis of 3'-methyl-[1,1'-biphenyl]-4-carbaldehyde from 3-methylphenylboronic acid and 4-formylphenylboronic acid: arylboronic acid (0.5 mmol) and K2CO3 (1 mmol, 138.0 mg) were added to a 20 mL Schlenk tube fitted with a non-magnetic stir bar. The tube was evacuated twice and backfilled with N2. MeCN (2 mL) and I2 (0.75 mmol, 191 mg) were added to the tube at room temperature. The tube was sealed and placed in a preheated oil bath at 80 °C for 8-12 h under a stream of N2 gas for the reaction. After the reaction mixture was cooled to room temperature, acrylic boronic acid (0.75 mmol) and Pd(OAc)2 (0.025 mmol, 5.6 mg) were added and the mixture was stirred at 80 °C for 12-16 hours. After completion of the reaction, the mixture was cooled to room temperature and quenched by the addition of H2O (10 mL). The aqueous layer was extracted with EtOAc (3 x 5 mL). The organic phases were combined, dried with anhydrous Na2SO4, filtered and concentrated by rotary evaporation. The residue was purified by silica gel column chromatography to afford the target product 3'-methyl-[1,1'-biphenyl]-4-carbaldehyde. Experimental data are provided for three representative examples.
References
[1] Synlett, 2014, vol. 25, # 7, p. 995 - 1000
