羧酸酯一般来说较易被还原伯醇，其常用的方法为金属钠和醇 Na-EtOH；金属氢化 物如氢化铝锂(LAH), 硼氢化钠（钾）等。其中金属氢化物是为常用的还原剂。 

1.  金属钠和醇为还原剂（Bouveault-Blanc 反应） 

    本反应是将羧酸酯用金属钠和无水醇直接还原生成相应地伯醇，主要用于高级脂肪 羧酯的还原。 

    由于催化氢化和氢化铝锂的广泛应用，此法在实验室中已经很少采用，但是因为其 简便易行，在工业上仍然广泛应用。Bouveault-Blanc 反应的历程可能如下： 

 金属钠和醇为还原剂（Bouveault-Blanc 反应）示例 

    The central neck of a 5-l. three-necked round-bottomed flask is fitted with a stopper carrying a mercury-sealed mechanical stirrer. One of the side necks is connected by means of a short piece of heavy rubber tubing to a large reflux condenser about 2 m. long, with an inner tube 2.5 cm. in diameter. The third neck is fitted with a separatory funnel. 

       In the flask are placed 70 g. (3 moles) of sodium and 200 cc. of dry toluene. The flask is heated in an oil bath until the sodium is melted. The stirrer is then started; when the sodium is finely divided, the oil bath is removed and the mixture allowed to cool. Stirring must be continued during the cooling in order to keep the sodium finely divided. 

      When the mixture has cooled to about 60°, there are added from the separatory funnel, first, a solution of 114 g. (0.5 mole) of ethyl laurate in 150 cc. of absolute alcohol, then 500 cc. more of alcohol, as rapidly as is possible without loss of material through the condenser. The time required for the addition of the ester solution and the alcohol is less than five minutes, usually two or three minutes. When the reaction has subsided, the flask is heated on a steam bath until the sodium is completely dissolved. The mixture is then steam-distilled to remove the toluene and ethyl alcohol. The contents of the flask are transferred to a separatory funnel while still hot and washed three times with 200-cc. portions of hot water to remove the sodium laurate. The lauryl alcohol is extracted with ether from the cooled mixture and the washings. The combined ether extracts are washed with water, sodium carbonate solution, and again with water, and dried over anhydrous magnesium sulfate. The ether is evaporated and the lauryl alcohol distilled under diminished pressure. The yield is 60–70 g. (65–75 per cent of the theoretical amount) of a product boiling at 143–146°/18 mm. or 198–200°/135 mm. 

        2.金属氢化物为还原剂 

        羧酸酯用 0.5 mol 的氢化铝锂还原时，可得到伯醇。 

      如仅用 0.25mol 并在低温下或降低氢化铝锂的还原能力，可使反应停留在醛的阶段。

      降低氢化铝锂还原能力可以提高还原反应的选择性。常用的的方法是加入不同比例 的无水三氯化铝或者加入计算量的醇，取代氢化铝锂中 1-3 个氢原子而成铝烷、或烷氧 基氢化铝锂。如用烷氧基氢化铝锂还原α,β-不饱和酯到α,β-不饱和醇，若单用氢化铝 锂还原，则得到饱和醇。 

     单纯使用氢化硼纳纳还原酯效果较差，若在 Lewis 酸如 AlCl3,ZnCl2 存在下，还原 能力大增，可顺利的还酯，甚至可还原某些羧酸。 

     由氢硼化钠和酰基苯胺在α-甲基吡啶中反应，生成的酰苯胺氢硼化钠是还原酯的 有效试剂。其优点：反应操作简便，不需要无水条件，反应选择性好。 

 LAH 还原羧酸酯成伯醇示例 

    利用 LAH 还原羧酸酯到伯醇是一个快速，后处理较为简便的方法，一般情况下， 酯基可在零下 30℃下反应 30 分钟即可被还原。因此即使分子内有酰胺或其他一些敏感的官能基存在也没什么关系。 

      A dry, 500-mL, three-necked, round-bottomed flask is equipped with a 150-mL pressure-equalizing addition funnel, a reflux condenser topped with an inert atmosphere line, a glass stopper, and an egg shaped magnetic stirring bar. The flask is charged with lithium aluminum hydride (2.66 g, 0.070 mol) and anhydrous ether (50 mL). The flask is cooled to 5°C in an ice-water bath. A solution of (2R)-methyl 4-(tert-butyldimethylsilyloxy)-2-(dimethylamino)cyclohex-3-enecarboxylate (22.4 g, 0.072 mol) in ether (80 mL) is transferred to the addition funnel and added over a 30-min period. The reaction mixture is stirred for another 15 min, diluted with ether (100 mL), and quenched by dropwise addition of water (9 mL). The ice-water bath is removed, the resulting gray suspension is allowed to reach room temperature, and the mixture is stirred vigorously for an additional 60 min. The mixture is transferred to a 1.0-L Erlenmeyer flask and diluted with 350 mL of ether. Anhydrous sodium sulfate (Na2SO4) (60 g) is added, the suspension is stirred for 30 min, and filtered. The filter cake is washed twice with ether (50 mL each time). The solvent is removed on a rotary evaporator and the remaining volatile material is removed under high vacuum to afford 18.6 g (91%) of ((2S)-4-(tert-butyldimethylsilyloxy)-2-(dimethylamino)cyclohex-3-enyl)methanol as a viscous clear oil. 

异丁醇铝还原α,β-不饱和酯到α,β-不饱和醇示例 

      To a solution of 3-(1H-benzoimidazol-5-yl)-acrylic acid methyl ester (50 mg in 1 ML dry tetrahydrofuran) at -78.deg. C. was added 1.24 NL of a 1M solution of lithium tri-sec-butylborohydride in tetrahydrofuran and the mixture stirred at -78.deg. C. for 4 hours followed by warming to -40.deg. C. for an additional 4 hours。

    The reaction was quenched by addition of aqueous methanol, concentrated in vacuo and purified by flash chromatography on silica gel (methylene chloride:methanol, 87:13) to give the title compound (44 mg). 

 硼氢化钠（钾）还原羧酸酯成伯醇示例 

      利用硼氢化钠（钾）还原羧酸酯到伯醇操作较为安全，简单的方法，由于硼氢化钠的还原性不够强，因此这类反应一般需要回流过夜。反应初始阶段不要去加热，而是在室温下搅拌数小时后在，再加热缓缓回流，否则反应极容易喷出来。硼氢化钠在甲醇中 分解较快，这个反应尽量不要用甲醇做溶剂。 

     To a stirred suspension of 58.5g (300mmol) of dimethyl pyridine-2, 6-dicarboxylate in 800ml of anhydrous ethanol was added in portions 53.0g (1400mmol) of sodium borohydride at 0°C, after stirring for 1h at 0°C, the ice bath was removed and the ongoing exothermic reaction caused the solution to boil under reflux. Stirring was continued for 3h, then the solution was heated under reflux for another 10h. The solvent was distilled off and the residue was digested with 200ml of acetone. The acetone was distilled off; to the residue was added 200ml of a saturated aqueous solution of K2CO3 and the whole was heated for 1h with a boiling water bath. The solvent was again distilled off, the residue was dissolved in 800ml of water, and sodium chloride was added in portions with stirring until a colorless precipitate was formed. The product was extracted three times, each time with 150ml of chloroform, the combined organic phases were dried with MgSO4 and filtered. The solvent was distilled off to give 37.8g (91%)of desired product as colorless needles 

 NaBH4-ZnCl2 还原酯示例 

     To a suspension of ZnCl2 (80.36 g, 0.591 mol) in dry THF (1000 mL), NaBH4 (11.2 g, 0.3043 mol) was added in portions at 0~5℃ under nitrogen. The mixture was stirred for 30 min at 20~25 ℃, The mixture was cooled to 0~5 ℃ and compound (S)-diethyl 2-(triisopropylsilyloxy)succinate (82 g, 0.2368 mol) was added dropwise at 0~5 ℃. Then the mixture was warmed to 55~60 ℃ and stirred for 18 hours. After confirming the completion of reaction by HPLC, The result reaction mixture was cooled to -15~-10 ℃. Water (213 mL) was added dropwise to quench the reaction at -15~-10 ℃. The reaction was aged for 3 h at 20~25 ℃. Charged celite (12.3 g) to the mixture and then the solid was removed by filtration. The filtrate was concentrated under vacuum to remove THF. And the filter cake was washed with CH2Cl2 (250×3 mL). The combined organic layers were washed with water (200 mL) and the mixture was separated and the organic layer was dried over Na2SO4. The solution was concentrated to give compound (S)-2-(triisopropylsilyloxy)butane-1,4-diol  (44.68 g, 0.170 mol, yield 71.9%).