Metal‐Free Cascade 1,4‐Conjugate Addition/Selective Annulation Strategy for Divergent Synthesis of Polysubstituted Imidazoles and 4‐Alkenylquinazolines
作者:Qiang Tang、Keke Xu、Xinwei He、Yongjia Shang
DOI:10.1002/adsc.202200905
日期:2022.12.8
metal-free cascade annulation of propagylamines with amidines for divergent synthesis of polysubstituted imidazoles and 4-alkenylquinazolines has been developed. The reaction is believed to proceed by sequential 1,4-conjugate addition of amidines to propargylamines, 5-exo-dig annulation/aromatization to form the polysubstituted imidazoles, and nucleophilic addition/elimination/aromatization to quinazoline
已经开发了丙胺与脒的无金属级联环化,用于多取代咪唑和 4-烯基喹唑啉的发散合成。据信该反应是通过将脒顺序地 1,4-共轭加成到炔丙基胺、5-外环化/芳构化以形成多取代咪唑以及亲核加成/消除/芳构化到喹唑啉骨架来进行的。在该反应中,范围广泛的富电子、电子中性和缺电子丙胺与脒反应良好,以 53-93% 的收率生成多取代咪唑和 4-烯基喹唑啉。此外,该方法的效用已通过克级实验和产物的合成转化得到展示。