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Comprehensive Summary: A Rh(III)‐catalyzed, transmetalation triggered C—H activation/annulation of 2‐biphenylboronic acids with diazo compounds from β‐keto esters or 1,3‐dicarboxylates has been developed, leading to the synthesis of two kinds of 9,10‐phenanthrenes. Notably, a rhodacyle was synthesized by treating the rhodium catalyst with stoichiometric amounts of 2‐biphenylboronic acids and pyridine, which was further verified to be active for the catalytic system. The reactions proceeded under redox‐neutral and air‐tolerant conditions to produce a series of all‐carbon six‐membered rings with high efficiency. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Divergent synthesis of useful skeletons has been realized via rhodium(III)‐catalyzed C—H activation of iminopyridinium ylides and coupling with various unsaturated coupling reagents. Isocoumarins and isoquinolones were obtained via cleavage of the C—N or N—N bond in the ylidic directing group, while fluorinated alkenes were delivered with the directing group intact. The reactions occurred with wide substrate scopes and good efficiency under redox‐neutral and air‐tolerant conditions. Representative products exhibit solid‐state fluorescent property and bioactivity of inhibition toward human cancer cells. [ABSTRACT FROM AUTHOR]