Norrish-Yang Reaction

Norrish-Yang Reaction

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  • General Characteristics

In the Norrish-Yang reaction, the C-H bond at the γ-position of ketones is homolytically cleaved by photo-irradiation and the ensuing rearrangement leads to the formation of cyclobutanols.

  • General References

<Photochemical reactions in total synthesis>

  • Reaction Mechanism

The radicals formed by the Norrish type II reaction form a new C-C bond.


  • Examples

An application to the synthesis of ouabagenin.[1]


The synthesis of paulownin[2]: This is an interesting variant case where the γ-position does not have a hydrogen.


Ketones containing a leaving group at the α-position undergo different modes of cyclization, such as the example shown here.[3]


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  • References

[1] Renata, H.; Zhou, Q.; Baran, P. S. Science 2013, 339, 59. doi:10.1126/science.1230631
[2] Kraus, G. A.; Chen, L. J. Am. Chem. Soc. 1990, 112, 3464. DOI: 10.1021/ja00165a033
[3] (a) Wessig, P.; Muhling, O. Angew. Chem. Int. Ed. 2001, 40, 1064. [abstract] (b) Wessig, P.; Muhling, O. Helv. Chim. Acta 2003, 86, 865. DOI: 10.1002/hlca.200390086

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