Isoindolinone Synthesis: Selective Dioxane-Mediated Aerobic Oxidation of Isoindolines

N-Alkyl and N-aryl-isoindolinones
were prepared by a dioxane-mediated oxidation of isoindoline precursors.
The transformation exhibits unique chemoselectivity for isoindonlines.
A chiral tertiary (3°)-benzylic position was not racemized during
oxidation, and methyl indoprofen was prepared by late stage oxidation.
Mechanistic studies suggest a selective H atom transfer, which avoids
many known oxidation (by-)­products of isoindolinones.