A versatile methodology for the regioselective C8-metalation of purine bases

Brackemeyer D., Hervé A., Schulte To Brinke C., Jahnke M. C., Hahn F. E.

Abstract

Purine nucleobases are excellent ligands for metal ions, forming normally coordinative Werner-type bonds by utilizing the N donor atoms of the nucleobase skeleton. Here we show that purines such as 8-chlorocaffeine and 8-bromo-9-methyladenine react with [Pt(PPh3)4] under oxidative addition of the C8-halogen bond to the metal center. The resulting PtII complexes feature a C8-bound ylidene ligand. Protonation of the ylidene at the N7/9-atom yields complexes bearing a protic N-heterocyclic carbene ligand derived from the purine base with an NMe,NH-substitution pattern. © 2014 American Chemical Society.