定义Definition
MPV 还原是用异丙醇铝在异丙醇中，把醛、酮选择性地还原为醇的反应；氢负离子从异丙氧基转移到底物羰基，异丙醇被氧化为丙酮。其逆反应称为奥彭瑙尔氧化。
The MPV reduction uses aluminium isopropoxide in isopropanol to reduce aldehydes and ketones selectively to alcohols; a hydride moves from an isopropoxide to the substrate carbonyl and isopropanol is oxidised to acetone. The reverse is the Oppenauer oxidation.
机理Mechanism
底物羰基与铝配位，铝上异丙氧基的 C–H 经六元环过渡态把氢负离子转移给羰基碳。蒸出生成的丙酮使平衡向醇移动。
The substrate carbonyl coordinates to aluminium, and the C–H of an isopropoxide transfers a hydride through a six-membered transition state. Distilling off acetone drives the equilibrium.
特点Features
化学选择性极高：C=C、硝基、卤素、酯基都不受影响；条件温和，试剂便宜、无毒。可用于 α,β-不饱和醛只还原羰基（如肉桂醛 → 肉桂醇）。
Highly chemoselective — alkenes, nitro groups, halides and esters survive; mild, cheap and non-toxic. α,β-Unsaturated aldehydes are reduced only at C=O (cinnamaldehyde → cinnamyl alcohol).
由来Origin
汉斯·迈尔外因（1925）、阿尔贝特·维尔莱（1925）和沃尔夫冈·庞多夫（1926）分别报道。
Reported by Hans Meerwein and Albert Verley (1925) and Wolfgang Ponndorf (1926).
反应Reactions
Al(OiPr)₃ 于异丙醇中回流，同时蒸出丙酮
Al(OiPr)₃ in refluxing isopropanol with removal of acetone
羰基与铝配位。
The carbonyl coordinates to aluminium.
六元环过渡态中氢负离子转移。
Hydride transfer through a six-membered TS.
醇盐交换释放产物醇。
Alkoxide exchange releases the product alcohol.
C=C 双键保留。
The C=C survives.
年表Timeline
- 1925
迈尔外因与维尔莱分别报道
Meerwein and Verley report it independently
- 1926
庞多夫报道
Ponndorf’s report
- 1937
奥彭瑙尔报道逆向氧化
Oppenauer reports the reverse oxidation