Terpenoids. Part 41. Reactions of ent-kaurenes and 13β-kaurenes with thallium(III) nitrate in 1,2-dimethoxyethane and a mutual allylic rearrangement of the allylic nitrate products
The reaction of ent-kaur-16-ene (1) or 13β-kaur-16-ene (4) with thallium(III) nitrate in glyme gave only allylic nitrate products, in high yield. The same reaction with ent-kaur-15-ene (16) gave the nitrates (2) and (3), an epoxide (22), and an allylic alcohol (5). Similar treatment of 13β-kaur-15-ene (21) afforded the allylic alcohols (9) and (10) and the ketones (23) and (24); considerable amounts of starting material were recovered. The significance of the differences between these reactions is discussed. A mutual allylic rearrangement of the allylic nitrate products is reported.