Addition to cumulated carbonyl groups and carboxylate ions

4 ADDITION TO CUMULATED CARBONYL GROUPS AND CARBOXYLATE IONS 

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

Indeed, the reaction with phenyl- or 1-naphthylisocyanate is sufficiently general to be recommended in traditional schemes for qualitative organic analysis (e.g. Ref [1]), as a general method for characterizing organic halides. However, it has been surprisingly little exploited in synthesis, although a Barbier adaptation promoted by sonication has been reported [2]. 

Analogous reactions of organomagnesium compounds with ketenes, giving enolates, also appear to be general [A]  

Although they have been very little exploited, one was recently used in the preparation of the isolable hindered enol (12) [3]. 

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