DDQ-Mediated Three-Component Dioxygenation of Alkenes.

A new DDQ-mediated three-component dioxygenation of alkenes has been established, providing a direct and metal-free access toward densely functionalized 4,5-dichloro-3-hydroxyphthalonitrile derivatives with generally good to excellent yields under mild conditions. During this process, DDQ plays dual roles as both a dehydrogenation reagent and a coupling partner, enabling oxidative coupling to form two C-O functionalities in a highly atom-economy fashion.