三级胺的氮氧化物热消除得到烯烃和N-羟基胺的反应。
反应机理
此反应是E2顺式消除反应,反应过程中形成一个平面的五元环过渡态,氧化叔胺的氧作为进攻的碱。要产生这样的环状结构,氨基和β-氢原子必须处于同一侧,并且在形成五元环过渡态时,α,β-碳原子上的原子基团呈重叠型,这样的过度态需要较高的活化能,形成后也很不稳定,易于进行消除反应。
图片来源:https://cheminfographic.wordpress.com/2018/01/17/66-cope-elimination-1949/
反应实例
固相Cope消除反应
逆-Cope消除反应
参考文献
Cope, A. C.; Foster, T. T.; Towle, P. H. J. Am. Chem. Soc. 1949, 71, 39293934. Arthur Clay Cope (1909-1966) was born in Dunreith, Indiana. He was a professor and head at MIT where he discovered the Cope elimination reaction after he taught at Bryn Mawr and Columbia where he discovered the Cope rearrangement. The Arthur Cope Award is a prestigious award in organic chemistry administered by the American Chemical Society.【 Arthur Clay Cope (1909-1966)生于印第安纳州的Dunreith,他麻省理工任教授期间发现了Cope消除反应,后又在布林茅尔学院和哥伦比亚大学任教,并发现了Cope重排反应。以他的名字命名的Arthur Cope奖是由美国化学会颁发的在有机化学方面非常著名的奖项。】
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编译自:Name Reactions (A Collection of Detailed Reaction Mechanisms), Jie Jack Li, Cope elimination reaction,page 159-160.