Synthesis of 2-ethoxy-2-carbethoxy-δ5 -dihydropyrans and their derivatives

Acrolein and methyl vinyl ketone undergo diene condensation with ethyl -ethoxyacrylate to give the corresponding 2-ethoxy-2-carbethoxy-⁵-dihydropyrans in 50–60% yields. The reduction of the latter with lithium aluminum hydride gave the hydroxymethyl derivatives of dihydropyrans, while ammonolysis gave amides of 2-ethoxy-⁵-dihydropyran-2-carboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 452–453, April, 1972.