醛类或酮类在碱性条件下与肼作用，羰基被可以被还原为亚甲基。此反应是Kishner (吉尔聂尔, 俄国人) 和Wokff (沃尔夫, 德国人)分别于 1911、1912 年发现的，故此而得名。原来Wolff-Kishner的方法是将醛或酮与肼和金属钠或钾在高温(约 200 °C)下加热反应，需要在封管或高压釜中进行。另外,此法要用金属钠以及难以制备和价值昂贵的无水肼。同时在应用此法还原时，若有极少量的水份存在，往往不可避免地要引起一些副反应。虽曾有人对此法进行过改良，但效果不显著。

      1946 年，黄鸣龙 3 对此法进行了卓有成效的改进。经他改良的方法，只需将酮类和醛类与氢氧化钾和氢氧化钠(代替金属钠)，85%(有时可用 50%)水合肼(代替无水肼)及双缩乙二醇或三缩乙二醇(代替封管或高压釜)，同置于圆底烧瓶内，回流 1 小时，移去冷凝管，继续加热，直到溶液温度上升至 190-200℃时，再插上冷凝管，保持此温度 23小时，然后按常规方法处理即得。若被还原的物质还原后的生成物沸点低于 190-200 ℃，则在蒸去水分时，物质亦随之逸去，故必须在冷凝管与烧瓶间装一分液管，借以除去水分。

例如：

      该法可同时适用于芳基和烷基酮的合成，但对碱或高温条件敏感的化合物不适合用此法还原。

反应机理

黄鸣龙还原芳基酮示例1

      A mixture of 18.2 g of benzophenone, 7 g of sodium hydroxide, 100 mL of triethylene glycol and 10 mL of 85% hydrazine hydrate was refluxed for 1 h. Then the condenser was removed until the temperature of the solution was had reached 195~200 ℃, when refluxing was continued for about three hours. The mixture was cooled and extracted with ether. The ether residue on distillation over sodium gave 14.0 g (83.3%) of pure hydrocarbon, b. p.149 ℃ at 29 mmg.

黄鸣龙还原二烷基酮示例2

     A reaction with 14.2 g (0.1 mol) of the ketone, 9 mL (0.18 mol) of hydrazine hydrate, 20 g of sodium and 400 mL of dithethlene glycol was carried out at 170-190 ℃ for sixty-eight hours. After dilution with water, extraction with ether. The organic layer was washed in turn with

water, dilute hydrochloric acid, and again with water. The extract was dried over anhydrous magnesium sulfate. Removal of solvent left the crude hydrocarbon, which was redistilled over sodium to give 8.95 g (70 %) of 2,6-dimethylheptane, bp 131-133℃ .