All-Carbon-Substituted Quaternary Carbon Atoms in Oxindoles by an Aerobic Palladium(II)-Catalyzed Ring Closure onto Tri- and Tetrasubstituted Double Bonds
作者:Julia A. Schiffner、Martin Oestreich
DOI:10.1002/ejoc.201001526
日期:2011.2
Oxidative palladium(II)-catalyzed cyclization of α,β-unsaturated amides derived from electron-rich anilines is reported. The aerobic ring closure of tri- and tetrasubstituted alkenes yields oxindoles with congested all-carbon-substituted quaternary carbon atoms. The ring-size selectivity is excellent. Selected unsymmetrically substituted arenes cyclize with perfect regioselectivity. Experimental evidence
据报道,氧化钯 (II) 催化的 α,β-不饱和酰胺环化源自富电子苯胺。三取代和四取代烯烃的有氧闭环产生具有拥挤的全碳取代季碳原子的羟吲哚。环尺寸选择性非常好。选定的不对称取代芳烃以完美的区域选择性环化。实验证据表明,该机制可能涉及 Friedel-Crafts 型亲电取代而不是直接的 C-H 键活化。