A New Synthesis of Alkenes from Vic-Diols Via Sulfite Esters

The preparation of olefins has been practiced for many years, but no regiospecific and stereospecific methods, using vic-diols as starting materials, were investigated until recent years. In this work, the preparation of cyclic sulfites of vic-diols was undertaken. These served as precursors to the olefins. The sulfites reacted with iodide ion to produce the olefins in most cases. Three sulfites: 4, 5-dimethyl-1, 3, 2-dioxathiolane-2-oxide, 4, 4, 5, 5-tetramethyl -1, 3, 2-dioxathlolane-2-oxide, and trans-1, 2 - cyclohexane sulfite, were prepared successfully from the corresponding vic-diols: 2, 3-butanediol, pinacol, and trans-1, 2-cyclohexanediol, respectively. The formation of the sulfites was supported by infrared, nuclear magnetic resonance, and mass spectral evidence. Attempts to prepare alkenes by react ion of the sulfites with iodide ion were successful in producing 2-butene and cyclohexene. However, all experiments directed toward the preparation of 2, 3-dimethyl -2-butene from pinacol sulfite failed