酯和另一种过量的醇在少量的碱或酸催化下共热，发生烷氧基转移，生成另一种酯。酯也可以和过量另外的酸的酰氯或活性酯进行交换得到新的酯。烯醇酯和酚类酯常用此方法合成。

反应实例一：

A mixture of Ethyl 2-cyano-3,3-diphenylacrylate (83.1 g，0.3 mol), cyclopentanol (100 mL) and Na2CO3 (6 g) were heated at 145℃ with disstillative removal of the ethanol formed, assisted by a stream of nitrogen. After about 3 h, the reaction mixture was filtered hot in order to remove the Na2CO3. After the filtrate had been cooled, the precipitate which had formed was filtered off, washed with petroleum ether and dried

to give cyclopentyl 2-cyano-3, 3-diphenylacrylate (78.1 g, 82%) as a colorless solid

反应实例二：

The mixture of 500 mg of 3-acetyloxy-7-[(5-nitro-2-pyridinyl)oxy]-1H-indene, 5 ml of benzoyl chloride and 15 mg of p-toluenesulfonic acid was stirred at 100℃. After stirring for 1.5 h, ethyl acetate was added to the reaction solution and the solution was washed in turn with a saturated sodium hydrogencarbonate solution and a saturated sodium chloride solution. The solution extracted with ethyl acetate was dried over anhydrous magnesium sulfate and the solvent was distilled off. The resulting residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=10:1)

to obtain 130 mg of 3-benzoyloxy-7- [(5-nitro-2-pyridinyl) oxy]-1H-indene as a white powder。

反应实例三：

A solution of 6-acetoxycholestan-3-one (1.215 g, 2.74 mmol) of isopropenyl acetate (15 mL) was refluxed in the presence of p-toluenesulfonic acid (20 mg) under argon for 3 h. Most of the solvent was removed and the concentrated mixture was extracted with ethyl acetate. The extract was washed with saturated NaHCO3, and brine, and dried over MgSO4. The residue obtained upon evaporation of the solvent was purified by column chromatography on silica gel (40 g) to give 2,6-Diacetoxycholest-2-ene(1.265 g, 95%)。

反应实例四：

5-Hexynoic acid (26.9 mg), 40.6 mg of 2-chloro-1, 3-dimethylimidazolinium chloride and 37.9 mg of pyridine were stirred in dichloromethane (10 mL) at room temperature for one h. Thereafter, 50 mg of 2,3-dimethyl-4-hydroxy-5, 6-difluoroquinoline was added thereto, and the mixture was stirred at room temperature for 15 h. Water was added to the reaction solution, and the mixture was extracted with dichloromethane. The dichloromethane layer obtained was washed with a saturated aqueous sodium hydrogencarbonate solution and was then dried over anhydrous sodium sulfate. The solvent was then removed by evaporation under the reduced pressure. The crude product thus obtained was purified on Wako Gel C-200 (10 g; elution solvent: hexane/EtOAc=10:1) to give 77.8 mg of 2,3-dimethyl-4- (5-hexynoylcarbonyloxy)-5,6-fluroquinoline。

反应实例五：

To the solution of Biotin (1.0 g, 4.1 mmol) in 20 mL of DMF, triethylamine (1 mL, 8mmol) was added followed by the addition of 2,3,5,6-tetrafhtororophenyl trifluoroacetate (1.76 g, 1 mmol) under argon atmosphere at 25℃. The reaction mixture was stirred at room temperature for 30 min and the solvent was removed under vacuum. The product was triturated in 10 mL of ether and filtered. The isolated product was dried under vacuum to yield biotin TFP ester (1.3 g, 80%) as a colorless

solid。

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