Towards a photochemical synthesis of peptides.

The laboratory preparation of peptides, once a challenge, is now a standard operation that can be automatised. However, the need for particular protecting groups requiring relatively harsh conditions for their removal (strong acids or bases) and reactive coupling agents can be problematic in specific cases (e.g. in a cell or in a microfluidic device). In this account, we describe our efforts towards a fully photochemical approach to peptide synthesis, where both the coupling and the deprotection steps use light instead of reagents. In order to selectively promote one of the two steps at a time, monochromatic light is used.