Late-Stage Diversification through Manganese-Catalyzed C-H Activation: Access to Acyclic, Hybrid, and Stapled Peptides.

Bioorthogonal C-H allylation with ample scope was accomplished through a versatile manganese(I)-catalyzed C-H activation for the late-stage diversification of structurally complex peptides. The unique robustness of the manganese(I) catalysis manifold was reflected by full tolerance of sensitive functional groups, such as iodides, esters, amides, and OH-free hydroxy groups, thereby setting the stage for the racemization-free synthesis of C-H fused peptide hybrids featuring steroids, drug molecules, natural products, nucleobases, and saccharides.