Abstract
Two of five isomers of 2, 3, 5, 6-tetramethyl-1, 4-dioxane were isolated. Their configurations were assigned with the coupling constants of the methine protons of the 1, 4-dioxane ring by nuclear magnetic resonance (NMR) spectrometry. 2, cis-3-Bis(Iodomethyl)-cis-5, trans-6-dimethyl-1, 4-dioxane (IIa) and 2, trans-3-bis-(iodomethyl)-trans-5, cis-6-dimethyl-1, 4-dioxane (IIb) were obtained by the cyclization reaction of meso- and dl-2, 3-butanediol, respectively, and 1, 3-butadiene with mercuric oxide and iodine. 2, cis-3, cis-5, trans-6-Tetramethyl-1, 4-dioxane (IIIa) and 2, trans-3, trans-5, cis-6-tetramethyl-1, 4-dioxane (IIIb) were obtained by reduction of IIa and IIb, respectively, with LiAlH4. The coupling constants and τ values of the methine protons of the 1, 4-dioxane ring were 3.3, 9.0 Hz, 6.16, 6.30, 6.54, 6.76 τ for IIIa, and 9.0 Hz, 6.77 τ for IIIb.
