Methionine-enabled peptide modification through late-stage Pd-catalyzed β-C(sp 3 )-H olefination/cyclization.

We present a method for site-selective diversification of peptides via Pd-catalyzed β-C(sp 3 )-H olefination/cyclization. In this protocol, the native methionine residue acts as a directing group, enabling site-specific olefination/cyclization of peptides. This chemistry demonstrates broad substrate scope, offering a versatile tool for peptide ligation.