4?Isobutyloxy?2?cyclohepten?1?one was prepared by the condensation of isobutyryl chloride and 4?hydroxy?2?cyclohepten?1?one.The effects of various amounts of 4?dimethylaminopyridine(DMAP),reaction temperature and reaction time on the esterification reaction were investigated under the condition of no condensation agent.The results show that the optimized reaction condition is 0.3 mmol of DMAP under 25 ℃ for 3 h with a yield of 89%.The results of the NMR show that the synthesized product was the target molecule 4?isobutyloxy?2?cyclohepten?1?one.This esterification reaction features high yields under mild reaction conditions without the involvement of condensation agents,which is in line with the concept of the development of green chemistry.