Wolff-Schroter rearrangement

This reaction is somewhat analogous to the Wolff-Schroter rearrangement (see below). 

Sus and his co-workers179 have applied the Wolff-Schroter rearrangement to 0-quinone diazides, which are accessible by diazotization of o-aminophenols and subsequent treatment with alkali. When irradiated, the quinone diazides lose nitrogen and pass into ketenes by ring contraction the ketenes are isolated as acids since the reaction is always effected in water. 

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