Iron(<scp>iii</scp>)-catalyzed selective N–O bond cleavage to prepare tetrasubstituted pyridines and 3,5-disubstituted isoxazolines from <i>N</i>-vinyl-α,β-unsaturated ketonitrones
作者:Chun-Hua Chen、Qing-Yan Wu、Cui Wei、Cui Liang、Gui-Fa Su、Dong-Liang Mo
DOI:10.1039/c8gc00630j
日期:——
An iron(III)-catalyst controlled cyclization and selective N–O bond cleavage of N-vinyl-α,β-unsaturated nitrones has been achieved under mild conditions to access tetrasubstituted pyridines and 3,5-disubstituted isoxazolines in moderate to good yields. The tetrasubstituted pyridines were afforded with FeCl3 as a catalyst while using FeCl3·6H2O combined with 1,10-phenanthroline delivered isoxazolines
在温和的条件下,以中等至良好的产率获得四取代吡啶和3,5-二取代异恶唑啉,已实现铁(III)催化剂控制的环化和N-乙烯基-α,β-不饱和硝酮的选择性N–O键裂解。用FeCl 3作为催化剂提供四取代的吡啶,同时使用FeCl 3 ·6H 2 O与1,10-菲咯啉传递的异恶唑啉组合。N中苯乙烯基环化的区域选择性吡啶和异恶唑啉的形成过程中,-乙烯基-α,β-不饱和硝酮完全不同。在进一步的对照实验研究的基础上,提出了形成吡啶和异恶唑啉的合理机理。当将乙酸铜(II)与制备的双齿N-配体结合使用时,可将异恶唑啉经四个步骤转化为新的双齿N-配体,并且从N-乙烯基硝酮获得环氧吡啶骨架。