Mechanochemical palladium-catalyzed C(sp2)-H homocoupling of N-arylcarbamates: synthesis of 2,2-biaryldiamines

The palladium-catalyzed dehydrogenative C(sp(2))-H homocoupling of N-arylcarbamates under high-speed ball-milling conditions has been achieved using weakly coordinating directing groups, providing access to a variety of 2,2-biaryldicarbamates which are readily converted to 2,2-biaryldiamines. The mechanochemical process occurs in the absence of solvent and does not require any additional heating.