8.5.2 Sommelet-Hauser Rearrangement

In the absence of β -carbonyl group, the α -hydrogen is too weakly acidic for hydroxide ion induced rearrangement. Thus, a strong base, such as amide ion in liquid ammonia, is to be used, when the rearrangement takes a different course: instead of [1,2] shift (Steven's rearrangement), a [3,2]-sigmatropic rearrangement takes place which is called Sommelet- Hauser rearrangement.

Mechanism

There can be competition between Stevens and Sommelet-Hauser rearrangement mechanisms.

Examples: