A novel palladium(0)-catalyzed cyclization to 3,4-disubstituted pyrrolidin-2-ones has been developed. The new approach relies upon the concomitant generation of stabilized acetamide enolate anions and of a pi-allyl-palladium appendage, properly tethered by a nitrogen atom. Reaction conditions have been optimized for the methoxycarbonyl-stabilized model reaction [(Z)-2 --> 3] and then applied to other
已开发出新颖的
钯(0)催化环化为3,4-二取代的
吡咯烷-2-
酮。新方法依赖于稳定生成的乙
酰胺烯酸根阴离子和由
氮原子适当束缚的π-
烯丙基-
钯附件。已针对甲
氧基羰基稳定的模型反应[(Z)-2-> 3]优化了反应条件,然后将其应用于其他底物。已显示范围广泛的乙
酰胺阴离子稳定剂可实现所需的分子内CC键形成(MeO(2)C,MeCO,NC,(EtO)(2)PO,PhSO(2))。环化仅产生5-exo-trig闭环,从而得到γ-内
酰胺。所有的环化反应都给出了相应的3,4-二取代的
吡咯烷基-2-
酮,具有总的非对映选择性。