Isocyanates, reaction with Grignard reagents

The addition of Grignard reagents to isocyanates gives, after hydrolysis, N-substituted amides. This is a very good reaction and can be used to prepare derivatives of alkyl and aryl halides. The reaction has also been performed with... 

The reaction of Grignard reagents with isocyanates is a good general method for preparing amides [A] ... 

Anilides, toluides, and a-naphthalides ate prepared from phenyl, p-tolyl, and a.-naphthyl isocyanates, respectively, by reaction with a Grignard reagent. The reaction is valuable for the identification of halogen compounds of the type that form organometallic derivatives. The reaction occurs in ether solution at room temperature. In general, the yields of N-arylamides are excellent. This method has been used in the preparation of N-(a.-furyl)-propionamide (89%). ... 

Primary amides. The reaction of a Grignard reagent with an isocyanate usually leads to a secondary amide ... 

---