Direct C-H arylation of purines: development of methodology and its use in regioselective synthesis of 2,6,8-trisubstituted purines.

[Structure: see text] Direct C-H arylation of purines to position 8 by diverse aryl iodides was achieved with Pd catalysis in the presence of CuI and Cs2CO3. The methodology is general and efficient and was applied in the consecutive regioselective synthesis of 2,6,8-trisubstituted purines bearing three different C-substituents in combination with two cross-coupling reactions.