Curtius rearrangement

The Curtius rearrangement was first reported by Theodor Curtius in 1890. This rearrangement, which is also called the Curtius reaction or Curtius degradation, proceeds via a highly versatile isocyanate intermediate which can be easily trapped by a variety of nucleophiles, including water, alcohols, and amines via a concerted mechanism which proceeds with retention of configuration. Therefore, this Curtius rearrangement is one of the most widely used organic reactions, with numerous recent examples in the literature.