Stereostructure of 2-ethynyl-substituted 2,4,4-trimethyl-1,3-dioxanes

It has been shown by PMR spectrometry and x-ray structure analysis that the six-membered 1,3-dioxane ring of 2-ethynyl-substituted 2,4,4-trimethyl-1,3-dioxanes, either in solution or in the solid state, exists in a nearly ideal chair conformation with an axial position of the ethynyl substituent. Kuban State Technological University, Krasnodar 350072, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 163–169, February, 1998.