Enamides via long-distance migration of double bonds

A new method for preparation of enamides (N-(alken-1-yl) amides) by means of the ‘long-distance' migration of the double bond in unsaturated amides in the presence of [Fe(CO)5] is described. The method is shown to be particularly useful for the isomerization of N-(but-3-enyl)amides, while, in the case of N-(pent-4-enyl) and N-(hex-5-enyl) amides the mixture of products was formed and the yield of the enamide was relatively low.