Osmium-promoted σ-bond activation reactions on nucleosides

Abstract

OsH6(PiPr3)2 has been used to selectively activate C–H, O–H, and C–C sigma bonds in nucleobases and nucleosides, including derivatives of 6-phenylpurine and 4-phenylpyrimidine, leading to cyclometalated mononuclear Os–trihydride complexes, in excellent yields and as single products. Additionally, OsH6(PiPr3)2 promotes the efficient dehydrogenative decarbonylation of primary alcohols in nucleosides having unprotected sugar moieties. The incorporation of OsH2Cl2(PiPr3)2 in the structure of cyclometalated Ir(III) and Rh(III) half-sandwich complexes derived from nucleosides allows the preparation of a class of heterobimetallic bioorganometallic complexes having at least one M–C bond. These methodologies could be used in the future as a way for the orthogonal functionalization of oligonucleotides.