Combining Trifunctionalization of Alkynoic Acids, Arene ortho C–H Functionalization and Amination: An Approach to Unsymmetrical 2,3-Diaryl Substituted Indoles

Here we report a simultaneous construction of two C-C and two C-N bonds in a unified procedure that incorporates alkynoic acid trifunctionalization, ortho C-H functionalization, and amination cascade. In an ordered process, the regioselective alkyne insertion reaction is favored over the decarboxylation process. The presence of the carboxyl group in alkynoic acid ensures the high regioselectivity in the carbopalladation process, paving the way for a novel method to synthesize unsymmetrically 2,3-diaryl substituted indole scaffolds with excellent regioselectivity. The protocol is demonstrated to be suitable for gram-scale synthesis.