Synthesis and intramolecular cyclization of propargyl ethers derived from 1-bromo(iodo)-3-organyloxy-2-propanol

The interaction of bromine (iodine)-releasing reagents, such as N-bromosuccinimide (NBS) or a mixture of iodine and clinoptilolite ((NaK)4CaAl6Si30O72), with an equimolar mixture of 3-organyloxy-1-propene and propynol results in the formation of propargyl ethers of 1-bromo(iodo)-3-organyloxy-2-propanol. The outcome of the catalytic hydration reaction of these ethers depends on the halogen atom present. Bromo derivatives are converted into the expected keto-bromo ethers, whereas iodo derivatives undergo simultaneous hydrolysis of the C–I bond and intermolecular ketalization, forming hydroxy derivatives of 1,4-dioxane. The hydration products of propargyl ethers derived from 1-bromo-3-organyloxy-2-propanol serve as key compounds for the synthesis of 2,2,5-trisubstituted 1,4-dioxanes through intermediate hydroxy diethers formed via reactions with organomagnesium reagents. The reactions and purity of the synthesized compounds were monitored using thin-layer chromatography. The yields of allyl ethers were higher than those of propargyl ethers. Some physicochemical properties of the synthesized compounds were measured, their composition and structure were confirmed by elemental analysis, and their identities were verified using IR and NMR spectroscopy.