Lewis Acid-Catalyzed Chemodivergent and Regiospecific Reaction of Phenols with Quaternary Peroxyoxindoles

The indium-catalyzed regiospecific coupling of substituted
phenol
derivatives and quaternary peroxyoxindoles for the synthesis of C2
or C4 benzoxazin-3-one-substituted phenols via skeletal rearrangement
is described. This reaction is demonstrated with 17 examples with
good yields and diverse aryl substituents. In contrast to the indium-catalyzed
reaction, the Cu­(OTf)2-catalyzed reaction of the phenol
with quaternary peroxyoxindoles afforded C2 or C4 2-oxindole-substituted
phenol derivatives. This diverse catalytic reaction generated various
biologically important phenol-substituted 2-oxindole derivatives directly
without any skeleton rearrangement and was demonstrated with 19 examples
in high yield. The regiospecificity and the reaction pathways were
explained with the support of density functional theory (DFT).