Synthesis of Substituted 2-Pyridones via the Pummerer Cyclization−Deprotonation−Cycloaddition Cascade of Imidosulfoxides
作者:Albert Padwa、Todd M. Heidelbaugh、Jeffrey T. Kuethe
DOI:10.1021/jo982315r
日期:1999.3.1
p-toluenesulfonic acid results in ring opening to give 5-acetoxy-substituted 2-pyridones. The lone pair of electrons on the amide nitrogen assists in opening the oxy bridge to generate a transient N-acyliminium ion, which subsequently loses a proton. In certain cases, the amide electron pair with the oxy bridge is partially twisted from an antiperiplanar arrangement and a competive ring cleavage also occurs to