1.It was shown that the pyrolysis of acetoacetic esters of enynols is accompanied by an intramolecular rearrangement occurring in the direction of the double bond, and not the triple bond; only enynic ketones are formed; no formation of polyenic ketones occurs:2.It was shown that the pyrolysis of 2-methyl-3,5-hexadien-2-ol acetoacetate proceeds without rearrangement of the double bonds with formation of the corresponding tertiary dienic ketone:3.In the cases described, the pyrolysis of acetoacetic esters is accompanied by cleavage processes with formation of acetone and the corresponding hydrocarbons: