Ir(III)-Catalyzed Aromatic C-H Bond Functionalization via Metal Carbene Migratory Insertion

Ir(III)-catalyzed coupling of aromatic C-H bonds with diazomalonates has been achieved successfully via a metal carbene migratory insertion process. With different types of carbamoyl directing groups, a wide range of arenes, including heteroarenes, can be used as substrates in this Ir(III)-catalyzed C-H functionalization reaction. Mono- and bisfunctionalized products can be obtained selectively simply by changing the number of equivalents of the diazo substrate. Moreover, when diazomalonates bearing one or two tert-butyl groups are used as the substrates, the C-H bond functionalization is followed by decarboxyation, leading to products with a -CH2CO2Me or -CH2CO2H moiety at the position ortho to the directing group. This reaction demonstrates that direct C-H activation and the metal carbene migratory insertion can be merged into one catalytic cycle with an Ir(III) complex as the catalyst.