ortho- and meta-Selective C–H Activation and Borylation of Aromatic Aldehydes via in situ Generated Imines

A ligand-controlled discovery of ortho and meta C–H boryl­ation of aromatic aldehydes is described. In both cases, an amine is used and it was proposed that ortho borylation could be realized using tert-butylamine as the traceless protecting/directing group and meta boryl­ation undergoes via an electrostatic interaction and a secondary interaction between the ligand of the iridium catalyst and the substrate. Remarkably, these electrostatic interactions and secondary B–N interactions offer a unique and unprecedented guiding factor for the meta-selective C–H activation/borylation of benzaldehydes. This is the first example for the C–H activation and functionalization where the ortho and meta position of a substrate has selectively been functionalized, which open a new chapter in electrophilic aromatic substitution chemistry. 1 Introduction 2 C–H Activation and ortho Borylation of Benzaldehydes 3 C–H Activation and meta Borylation of Benzaldehydes 4 Conclusion