Acid Catalyzed Reaction of 1-Octene and 2-Octene with Formaldehyde

Abstract

Prins reaction, known as acid catalyzed condensation of formaldehyde with an olefin, gives rather complex mixture of products, mainly composed of 1, 3-dioxanes and tetrahydropyranols, with minor amount of tetrahydrofuran derivatives, unsaturated alcohol and alcohol derived from hydration of the starting olefin. In this paper authers investigated the Prins reaction of both 1-octene and 2-octene. The products were isolated by fractional distillation and were purified by gaschromatography. On the reaction of 1-octene, the major products were found to be 4-hexyl-1, 3-dioxane and both cis- and trans-3-pentyl-tetrahydropyranol-4. The minor products consisted of 3-pentyltetrahydrofuran, 2-octanol and trans-3-nonene-l-ol. On the other hand, with the reaction of 2-octene, the major products were found to be 4-pentyl -5-methyl-1, 3-dioxane, 4-methyl-5-pentyl-1, 3-dioxane and the stereoisomer of 3-methyl-5-butyl-tetrahydropyranol-4. The minor products consisted of 2-methyl-4-butyltetrahydrofuran, 2-octanol and 2-methyl-3-octene-1-ol. The conformation of isomeric dioxanes and tetrahydropyranols were determind by NMR.