Synthesis
GENERAL METHOD: Iodine (0.1573 g, 0.62 mmol) was dissolved in dichloromethane (2 mL) at 0 °C, followed by a one-time addition of triphenylphosphine (0.1626 g, 0.62 mmol). Next, p-chlorobenzoic acid (0.41 mmol) was added to the mixture, and triethylamine (0.17 mL, 1.23 mmol) was added at 0 °C. The reaction mixture was gradually warmed to room temperature and stirred continuously until the reaction was complete (usually about 10 minutes). Upon completion of the reaction, the crude product was concentrated under reduced pressure and subsequently purified by column chromatography (CC) using a hexane solution of 5-10% ethyl acetate as eluent to give the final 4-chlorobenzoic anhydride.
References
[1] Tetrahedron Letters, 2016, vol. 57, # 3, p. 325 - 328
[2] Synthesis, 1981, # 8, p. 616 - 620
[3] Tetrahedron Letters, 1986, vol. 27, # 41, p. 4937 - 4940
[4] Synthesis, 1981, # 3, p. 218 - 220
[5] Synthetic Communications, 1983, vol. 13, # 6, p. 471 - 488
