Johnson–Claisen原乙酸酯重排

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在少量弱酸存在下,加热烯丙醇类化合物与过量的原乙酸三酯反应得到γ,δ-不饱和酯的反应。


反应机理

机理同Claisen重排(Claisen重排反应),原乙酸酯先和烯丙醇反应生成原乙酸混酯,其失去一个醇得到乙烯缩醛,接着发生[3,3]-σ单电子重排得到γ,δ-不饱和酯。



反应实例

 J. Am. Chem. Soc. 1987, 109, 3025–3036】.



【 J. Org. Chem. 1993, 58, 4280–4286】.




Angew. Chem. Int. Ed. 1998, 37, 2085–2087】.




Bioorg. Med. Chem. Lett. 2005, 15, 1647–1650】.




Org. Lett. 2008, 10, 681–684】 .



Johnson, W. S.; Werthemann, L.; Bartlett, W. R.; Brocksom, T. J.; Li, T.-t.; Faulkner, D. J.; Peterson, M. R. J. Am. Chem. Soc. 1970, 92, 741. William S. Johnson (1913-1995) was born in New Rochelle, New York. He earned his Ph.D. in only two years at Harvard under Louis Fieser. He was a professor at the University of Wiscon sin for 20 years before moving to Stanford University, where he was credited with building the modern-day Stanford Chemistry Department.


参考文献



Name Reactions (A Collection of Detailed Reaction Mechanisms), Jie Jack Li, Johnson–Claisen orthoester rearrangement, page 150-151.

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