Unexpected ring contraction and oxidation rearrangement reactions of securinine

The bromination and oxidation of securinine were studied. An interesting and surprising rearrangement was observed during the reaction of securinine with tribromo-isocyanuric acid or 1,3-dibromo-5,5-dimethylhydantoin in methanol, yielding a stereoselective ring contraction norsecurinine derivative. Meanwhile two oxidation rearrangement products were also reported. Some preliminary discussions on the reactivity of securinine were conducted from these rearrangements; it is believed to be induced by alkaline nitrogen atom of the molecule.

A ring contraction and an oxidation rearrangement of securinine were reported. Especially the six-membered piperidine ring was contracted to five-membered pyrrolidine ring, which could be used as a new method for organic synthesis. Some preliminary discussions on the reactivity of securinine were conducted from these rearrangements.Figure optionsDownload as PowerPoint slide