A novel peptide-peptide ligation strategy is introduced that has the potential to provide peptide libraries of linearly or branched coupled fragments and will be suited to introduce simultaneous protein modifications at different ligation sites. Ligation is assisted by templating peptide nucleic acid (PNA) strands, and therefore, ligation specificity is solely encoded by the PNA sequence. PNA templating, in general, allows for various kinds of covalent ligation reactions. As a proof of principle, a native chemical ligation strategy was elaborated. This PNA-templated ligation includes easy on-resin procedures to couple linkers and PNA to the respective peptides, and a traceless photocleavage of the linker/PNA oligomer after the ligation step. A 4,5-dimethoxy-2-nitrobenzaldehyde-based linker that allowed the photocleavable linkage of two bio-oligomers was developed.

Benzyltriazoles have been catalytically oxidized by using CuI and tert‐butyl hydroperoxide to yield phenyl(1H‐1,2,3‐triazol‐4‐yl)methanone derivatives in good yields at room temperature.

Copper catalyzed oxidation of benzyltriazoles with tBuOOH proceeds at room temperature to afford α‐keto‐1,2,3‐triazoles in good yields.