The general procedure for the synthesis of diethyl 2-(4-chlorophenyl)malonate from 4-bromochlorobenzene and diethyl malonate is as follows:
Example 6: Preparation of diethyl 2-(4-chlorophenyl)malonate by coupling reaction of 4-chlorobromobenzene with diethyl malonate
1. 191.5 mg (1 mmol) of 4-chlorobromobenzene and 160 mg (1 mmol) of diethyl malonate were dissolved in 5 mL of N,N-dimethylformamide (DMF), and 652 mg (2 mmol) of cesium carbonate was added to the reaction system under the protection of an inert gas, and the reaction mixture was stirred for 1 hour.
2. 17.9 mg (4 mol%) of HBPNS ligand and 9.0 mg (4 mol%) of palladium(II) acetate were added to the reaction system and the reaction mixture was subsequently heated to 80 °C and maintained at this temperature for 24 hours.
3. Upon completion of the reaction, post-treatment was performed: 5 mL of water and 10 mL of toluene were added to the reaction mixture, which was fully shaken and separated, and the lower aqueous phase was discarded. The organic phase was washed once more with 5 mL of water to remove residual DMF.
4. Finally, toluene was removed by rotary evaporator to give 230 mg (0.85 mmol, 85% yield) of the target product diethyl 2-(4-chlorophenyl)malonate.
