Synthesis of cyclic acetals of acetylenic carbonyl compounds

A condensation of α-acetylenic carbonyl compounds and their acyclic acetals with 1,2-diols gave substituted 1,3-dioxacycloalkanes in up to 90% yields. 2,4-Disubstituted 1,3-dioxolanes were formed as mixtures of steric isomers, in which trans-forms predominated according to the B3LYP/6-311+G(2d,p) calculations.