作者:Alan Armstrong、Alistair G. Draffan
DOI:10.1039/b107839a
日期:2001.11.1
The possibility of intramolecular epoxidation in acyclic unsaturated ketones (via dioxiranes) and oxaziridines (via oxaziridinium species) has been investigated. Treatment of several acyclic unsaturated ketones with Oxone® led to low levels of regio- and stereocontrol, suggesting that background epoxidation by Oxone® dominates. However, treatment of unsaturated oxaziridines with methyl trifluoromethanesulfonate led to intramolecular epoxidation. This process allowed regioselective epoxidation of a non-conjugated diene. It also proceeded with a high degree of stereocontrol consistent with a stereoelectronic preference for a spiro-transition state.
我们研究了无环不饱和酮(通过二氧环烷)和草吖啶(通过草吖啶鎓)分子内环氧化的可能性。用 Oxone® 处理几种无环不饱和酮时,会产生较低水平的区域和立体控制,这表明 Oxone® 的背景环氧化作用占主导地位。不过,用三氟甲磺酸甲酯处理不饱和恶嗪类化合物会导致分子内环氧化。这一过程允许对非共轭二烯进行区域选择性环氧化。此外,该过程还具有高度的立体控制性,这与立体电子学对螺烷基转变态的偏好是一致的。