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.