A photochemical C=C cleavage process: toward access to backbone -formyl peptides.

Photo-responsive modifications and photo-uncaging concepts are useful for spatiotemporal control of peptides structure and function. While side chain photo-responsive modifications are relatively common, access to photo-responsive modifications of backbone N-H bonds is quite limited. This letter describes a new photocleavage pathway, affording -formyl amides from vinylogous nitroaryl precursors under physiologically relevant conditions via a formal oxidative C=C cleavage. The -formyl amide products have unique properties and reactivity, but are difficult or impossible to access by traditional synthetic approaches.