Stereoselective Acetalization for the Synthesis of Liquid-Crystal Compounds Possessing a trans-2,5-Disubstituted 1,3-Dioxane Ring with Saturated Aqueous Solutions of Inorganic Salts

摘要

Stereoselective process for the synthesis of trans-2,5-disubstituted 1,3-dioxane derivatives, which are important liquid-crystal compounds, was developed. The acetalization reaction between aldehydes and 2-substituted 1,3-propanediols in the presence of acids gave the corresponding 2,5-disubstituted 1,3-dioxane derivatives with high trans selectivity (trans/cis = >96:<4), when the reaction was performed with saturated aqueous solutions of inorganic salts having high water solubility, such as CaCl2, LiCl, and ZnCl2.