Photoredox-Catalyzed Site-Selective Functionalization of Primary Amine Derivatives

Given the prevalence of primary amines in biologically active molecules, an important area of research is devoted to creating methods to site-selectively functionalize their C(sp³)-H bonds. For simple aliphatic primary amines, many of these C-H bonds are chemically indistinguishable due to their similar electronics and sometimes, steric environments. Through strategic choice of activating group, site-selective functionalization at both α- and ẟ- positions is achieved. Exploiting inductive effect allows for a photoredox-catalyzed α-C(sp³)-H alkylation of trifluoromethanesulfonamides. In the case of trifluoroacetamides, functionalization is directed to a distal C(sp³)-H site via [1,5]-hydrogen atom transfer which results in a formal delta-aminomethylation and delta-cyanation. Lastly, by subjecting primary amines to an electron-rich benzaldehyde activating group, we leverage C-N bonds as a functional handle for deaminative radical cross-couplings.