Nickel Catalyzed\nAryl–Aryl Bridging C–N\nBond Activation of 2‑Pyridylpyridones and 6‑Purinylpyridones

A Ni-catalyzed\nC–N bond activation of 2-pyridylpyridone\nand 1-(9-alkyl 9<i>H</i>-purin-6-yl)pyridin-2(1<i>H</i>)-one and coupling with arylboronic acid have been achieved. A unique\nfeature of this reaction is the strategic activation of the bridging\nC–N bond and replacement of the pyridone unit with aryl groups\nusing nickel catalyzed Suzuki–Miyaura coupling. This provides\nan exciting new tool to build C–C bonds in the place of pyridones.\nA wide variety of substrates and boronic acids are amenable to this\ntransformation. More importantly, we have successfully synthesized\na variety of C(6)-arylated purines via deaminative cross-coupling\nwhich are very useful in developing unnatural nucleobases, nucleotides,\nand nucleosides.