Palladium-Catalyzed Tandem Cyclization of Functional Diarylalkynes and Isocyanides for the Assembly of Isochromeno[4,3-]quinolines.

A novel strategy for the synthesis of various isochromeno[4,3-]quinolines via palladium-catalyzed tandem cyclization of functional diarylalkynes with isocyanides has been developed. This approach features excellent chemo- and regioselectivities as well as good functional group tolerance. Notably, 6-phenylimino-6-isochromeno[4,3-]quinolin-11-amines and 11-amino-6-isochromeno[4,3-]quinolin-6-ones can be selectively constructed by employing different protecting groups of functional diarylalkynes. The gram-scale and late-stage modifications further demonstrate the synthetic value of this method.