Ru(II)-Catalyzed Skeletal Editing of Oxindole with Internal Alkyne To Synthesize C7-Alkylated Indole Derivatives

A Ru(II)-catalyzed skeletal editing
of oxindole scaffolds
was established
to afford C7-alkyl acetate indole derivatives using internal alkyne
and alkyl alcohol. The developed method is simple, efficient, and
straightforward. The reaction was extended to substrates having wide
chemoselective profiles. When unsymmetrical alkynes were used, promising
regioselectivity was realized. A preliminary mechanistic study revealed
that the reaction pathway proceeded by Ru(II)/Ag(I)-catalyzed amide
cleavage and subsequent oxidative annulation.