Salt effects on the conformational behavior of 5-substituted 1,3-dioxanes

Since their introduction by E. L. Eliel nearly four decades ago, derivatives of 1,3-dioxane have proved useful in conformational analysis. Examples are discussed, where 5-polar substituents permit the evaluation of fundamental phenomena such as attractive and repulsive gauche effects, electrostatic interactions, and stereoelectronic effects. By the same token, 2-substituted 1,3-dioxanes, 1,3-dithianes, and 1,3-oxathianes are useful frameworks for the study of the anomeric effect and the associated structural and spectroscopic manifestations, such as the so-called Perlin effects. In view of the varied and essential involvement of metal ions and inorganic salts in biological processes, 5-substituted 1,3-dioxanes are presently being examined in the presence of Li+, Na+, K+, Ag+, Mg2+, Ca2+, Ba2+, and other cations, with the aim to increase the understanding of biomolecular properties in vivo.