Hofmann isonitrile synthesis carbylamine

This reaction was first reported by Hofmann in 1868. It is the synthesis of isonitriles (also known as isocyanides) from primary amines and chloroform in the presence of alkali and is known as the Hofmann isonitrile synthesis, Hofmann carbylamine reaction, or Hofmann carbylamine synthesis. This reaction has been used to test the presence of primary amines from the order of isocyanides. Alternatively, the isonitriles can be prepared by means of the treatment of formamide of primary amines with toluenesulfonyl chloride" or phosphorus oxychloride (POCls)." Currently, the isonitriles have gained much attention in organic synthesis because of their application as versatile building blocks for heterocycles and in multicomponent reactions to generate combinatorial libraries, such as that in the Passerini reaction and Ugi reaction ... 

The Hofmann carbylamine synthesis of isonitriles by the reaction of chloroform and base with primary amines was first reported over 100 years ago, but the reaction was not preparatively useful. For this reason, the two step process involving formyla-tion of the amine followed by dehydration was the method of choice. The phase transfer carbylamine reaction is inexpensive and convenient and the yields are such that it is competitive with the dehydration technique in many cases [13—15]. 

---