Curtius Degradation Utilizing Trimethylsilyl Azide. A facile isocyanate synthesis

We wish to report a modification of the Curtius Degradation which facilely affords high yields of isocyanates from acid chlorides or anhydrides under “single-pot” conditions. Trimethylsilyl acide attacks the reactive carbonyl groups of cyclic anhydrides and isomaleimides according to Eqn. 1, giving formally a Curtius Degradation product.