Domino Electrocyclization/Azide-Capture/Schmidt Rearrangement of Dienones: One-Step Synthesis of Dihydropyridones from Simple Building Blocks
作者:Dong Song、Ali Rostami、F. G. West
DOI:10.1021/ja071041z
日期:2007.10.1
proceed via nucleophilic trapping of the 2-oxidocyclopentenyl intermediate, followed by Schmidt-type rearrangement to give a transient 1,4-dipole. In unsymmetrical examples, complete regioselectivity in favor of attack on the less substituted side was observed. The 1,4-dipole intermediate then rearranges to the observed dihydropyridone, via either proton transfer or 1,5-hydride shift.
简单的 1,4-dien-3-ones 经历路易斯酸催化的 Nazarov 电环化和各种叠氮化物的分子间捕获,以中等至良好的产率提供 3,4-dihydropyridin-2-ones。建议该反应通过 2-氧化环戊烯基中间体的亲核俘获进行,然后进行施密特型重排以产生瞬时的 1,4-偶极子。在不对称的例子中,观察到完全的区域选择性有利于较少取代的一侧的攻击。然后,通过质子转移或 1,5-氢化物位移,1,4-偶极中间体重新排列为观察到的二氢吡啶酮。