Expedient Access to Unsymmetrical Diarylindolylmethanes through Palladium-Catalyzed Domino Electrophilic Cyclization–Extended Conjugate Addition Approach

A palladium-catalyzed domino process
to access unsymmetrical diarylindolylmethanes
has been developed through the annulation of o-alkynylanilines
followed by 1,6-conjugate addition with p-quinone
methides (p-QMs) under relatively mild conditions.
The broad substrate scope of this methodology was demonstrated through
the use of a wide range of substituted o-alkynylanilines
and p-quinone methides, and in most cases, the unsymmetrical
diarylindolylmethanes could be prepared in moderate to excellent yields.
Notably, this method does not require any amino group protection.
Moreover, 100% atom economy makes this transformation attractive from
a green chemistry perspective.