定义Definition
斯文氧化是用草酰氯活化的二甲基亚砜（DMSO）在 −78 °C 下把伯醇氧化为醛、仲醇氧化为酮，再加三乙胺完成消除的温和氧化方法；伯醇不会被过度氧化为羧酸。
The Swern oxidation uses dimethyl sulfoxide activated by oxalyl chloride at −78 °C, followed by triethylamine, to oxidise primary alcohols to aldehydes and secondary alcohols to ketones under mild conditions, without over-oxidation to acids.
机理Mechanism
DMSO 与草酰氯生成氯代二甲基锍离子（放出 CO 和 CO₂）；醇进攻硫生成烷氧基锍盐；三乙胺夺取甲基上的质子形成硫叶立德，经五元环过渡态分子内夺取醇碳上的 H，生成羰基化合物和二甲硫醚。
DMSO and oxalyl chloride form a chlorodimethylsulfonium ion (releasing CO and CO₂); the alcohol attacks sulfur to give an alkoxysulfonium salt; triethylamine deprotonates a methyl to a sulfur ylide, which removes the carbinol H through a five-membered transition state, giving the carbonyl and dimethyl sulfide.
由来Origin
丹尼尔·斯文与 K. Omura 等于 1978 年报道，是 DMSO 类氧化（菲茨纳–莫法特法等）中最常用的一种。
Reported by Daniel Swern with Kanji Omura and others in 1978 — the most popular of the DMSO-based oxidations (cf. Pfitzner–Moffatt).
优缺点Pros and cons
条件温和、无重金属、官能团兼容好、手性中心几乎不消旋。缺点：需 −78 °C 低温；副产物二甲硫醚恶臭，CO 有毒，须在通风橱中操作。替代方法有德斯–马丁氧化、帕里克–德林氧化、TEMPO 氧化。
Mild, metal-free, tolerant and non-epimerising, but it needs −78 °C, produces foul-smelling dimethyl sulfide and toxic CO, and must be run in a fume hood. Alternatives include Dess–Martin, Parikh–Doering and TEMPO oxidations.
反应Reactions
CH₂Cl₂，−78 °C 依次加入草酰氯、DMSO、醇，最后加 Et₃N 回温
CH₂Cl₂ at −78 °C: oxalyl chloride, DMSO, alcohol, then Et₃N and warming
活化 DMSO 生成氯代锍盐。
Activate DMSO to the chlorosulfonium salt.
醇与之生成烷氧基锍盐。
The alcohol forms an alkoxysulfonium salt.
三乙胺生成叶立德并分子内消除得羰基。
Et₃N forms an ylide that eliminates to the carbonyl.
仲醇氧化。
Secondary alcohol oxidation.
年表Timeline
- 1963
菲茨纳–莫法特 DMSO/DCC 氧化
Pfitzner–Moffatt DMSO/DCC oxidation
- 1978
斯文报道草酰氯活化法
Swern reports oxalyl-chloride activation