Vinyl Epoxides Compound Of The Thermal Rearrangement

Vinyl epoxy compounds were widely used in the field of organic synthesis as an important organic intermediates. They could undergo a series of reactions such as substitution, addition, elimination, and cycloaddition reactions due to its own structural characteristics. Therefore, they play an important role in the synthesis of organic compounds. Although vinyloxirane rearrangements catalyzed by acid have been widely researched, thermal rearrangements of vinyloxirane have not been reported at present. It’s quite significant to investigate the mechanisms of thermal rearrangements to disclose the essence of thermal rearrangements of vinyloxirane in synthetic field. In my paper, substituted 3-phenyl benzaldehyde derivativies were formed in the prescence of triethylamine which was a large steric base, however, ring-opening ketones only were obtained in the presence of small steric triethylenediamine. It’s pretty interesting that the thermal rearrangements of vinyloxirane can form substituted 3-phenyl benzaldehyde product through the unexpected rearrangement reaction in the presence of trimethylamine.Preliminary studies of the mechanism of thermal rearrangements of vinyloxirane showed that vinyl epoxy firstly underwent the radical process in thermal conditions, and formed unsaturated aldehyde intermediates, then the substituted 3-phenyl benzaldehyde was obtained after the Diels-Alder cycloaddition reaction of the enol intermediates. Accordingly, the epoxy group was attacked from the small side of the substrate in the presence of triethylenediamine if the substrate had small steric hindrance, further followed by the 1,2-hydrogen migration then the ketone was formed. However, thermal rearrangements of vinyloxirane was carried out in accordance with the above-described radical reaction when the substrate has large steric hindrance, and the substituted benzaldehyde was formed in the presence of triethylamine.