Penta-2,4-dienamides

Penta-2,4-dienamides have been obtained by stoichiometric Ni(II)-pro-moted oxidative aminocarbonylation of 1,3-butadiene (Eq. 16) [56]. 

At low temperatures arylcyclopropenones condense with enamines by 1,2-addition to give the 2-azoniabicyclo[3.1.0]hex-3-en-3-olates 344, which isomerize on heating to penta-2,4-dienamides 348. In an overall sense these products arise from insertion of the cyclopropenone three carbon unit into the C-N bond of the enamine and at elevated temperatures compounds 344 are not isolated. In certain instances, -aminoenones 345, co-aminocyclopentenones 347 and cyclopentenones 346 (next page) also ensue . Ketene acetals behave in a similar manner to enamines . 

Reaction of enamines with cyclopropenones produced penta-2,4-dienamide derivatives by cyclopropenone insertion into the enamine C-N bond (Table 1). ... 

Table 1. Penta-2,4-dienamides from Cyclopropenones and Enamines ...

A synthesis of substituted dihydropyridin-2(3/f)-ones has been reported from penta-2,4-dienamides in which an intramolecular C-N bond is formed via a thermal 6 r-azaelectrocyclization (Scheme 41). ... 

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