Iron-Catalyzed C-H Bond Functionalization for the Exclusive Synthesis of Pyrido[1,2-a]indoles or Triarylmethanols

The efficient and selective iron-catalyzed C-H activation of 2-benzhydrylpyridine derivatives was employed for the preparation of pyrido[1,2-a]indoles through an intramolecular C-H amination reaction. In the presence of molecular oxygen as the sole oxidant, the same 2-benzhydrylpyridines were also used for the synthesis of the corresponding tertiary alcohols. In these approaches, the iron catalyst was used to selectively activate the C(sp(2))-H bond of 2-benzhydrylpyridine, in the case of the intramolecular ring-closing C-H amination reaction in which the pyridine nitrogen atom was a directing group as well as a nucleophile, and the C(sp(3))-H bond of the same compound, in the case of the oxidation reaction to give the corresponding triaryl carbinol.