Although the reaction conditions for the substrates were mostly based on findings from building blocks reaction optimizations, single substrate optimization also proved of high utility for LSF examples (see SI). In case of Atazanavir, a single reaction conditions screening allowed us to rapidly identify optimal conditions for accessing the monofunctionalized product 3a and difunctionalized product 3a´ with high degree of selectivity in good to very good yields. Further worth noting is the compatibility of the reaction conditions with a number of polar and protic groups, including arrangements of functional groups suitable for bidentate coordination in the peptide backbone. The pyridine moiety also served as a suitable directing group in Priletivir. Compound 3b was successfully obtained, with the primary sulfonamide, thiazole and tertiary amide groups tolerated. The heavily substituted pyrazole of Apixaban served as a productive directing group, further demonstrating the utility of this moiety for directed C-H amination. Important noting is the use of NMP as the reaction solvent, as the substrate was insoluble in DCE. While the reaction offered relatively low isolated yield of 3c, the majority of Scheme 2. Scope: LSF. Directing groups highlighted in blue. Isolated yields shown.