Double CH Activation of a Masked Cationic Bismuth Amide

The transformation of C-H bonds into more reactive C-M bonds amenable to further functionalization is of fundamental importance in synthetic chemistry. We demonstrate here that the transformation of neutral bismuth compounds into their cationic analogues can be used as a strategy to facilitate CH activation reactions. In particular, the double CH activation of bismuth-bound diphenyl amide, (NPh2)(-), is reported along with simple one-pot procedures for the functionalization of the activated positions. The organometallic products of the first and second CH activation steps were isolated in high yields. Analysis by NMR spectroscopy, single-crystal X-ray diffraction, and DFT calculations revealed unusual ground-state properties (e.g., ring strain, moderate heteroaromaticity), and provided mechanistic insight into the formation of these compounds.