1,2-Wittig rearrangement

Encyclopedia : 1 : 12 : 12W : 1,2-Wittig rearrangement

A 1,2-Wittig rearrangement is an organic reaction and a 1,2-rearrangement of an ether with an alkyllithium compound.

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The intermediate product is an alkoxy lithium salt and the final product a alcohol. When R₂ is a good leaving group and electron withdrawing functional group such as a cyanide (CN) group, ^[1] this group is eliminated and the corresponding ketone is formed.

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The reaction mechanism centers on the formation of a free radical pair with lithium migrating from the carbon atom to the oxygen atom. The R₃ radical then recombines.

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References

G. Wittig, L. Löhmann, Ann. 550, 260 (1942)
G. Wittig, Experientia 14, 389 (1958).
^[1] Preparation of aryl benzyl ketones by [1,2]-Wittig rearrangement Alan R. Katritzky, Yuming Zhang, Sandeep K. Singh Arkivoc p. 146-150 2002 (vii)

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