α-Angelica lactone catalyzed oxidation of benzylic sp3 C-H bonds of isochromans and phthalans.

A metal-free organocatalytic system has been developed for highly efficient benzylic C-H oxygenations of cyclic ethers using oxygen as an oxidant. This oxidation reaction utilizes α-angelica lactone as a low cost/low molecular weight catalyst. The optimized reaction conditions allow the synthesis of valued isocoumarins and phthalides from readily available precursors in good yields. Mechanistic studies indicate that the reaction pathway likely involves a radical process via a peroxide intermediate.

α-Angelica Lactone in a New Role: Facile Access to N-Aryl Tetrahydroisoquinolinones and Isoindolinones via Organocatalytic α-CH2 Oxygenation.

A method for the direct oxidation of various N-aryl tetrahydroisoquinolines and isoindolines to the corresponding lactams using α-angelica lactone as a catalyst was developed. The utility of the method was further demonstrated by synthesis of indoprofen and indobufen.