The Furan–Thiol–Amine Reaction Facilitates DNA-Compatible Thiopyrrole-Grafted Macrocyclization and Late-Stage Amine Transformation

We here report an efficient DNA-compatible furan–thiol–amine reaction for macrocyclization and late-stage amine transformation. This reaction, conducted under mild conditions, enables the facile cyclization of DNA-conjugated linear peptides into thiopyrrole-grafted macrocycles regardless of ring size or side-chain modification with good to excellent conversion yields. Additionally, this strategy was employed for the late-stage transformation of terminal amines, serving as critical intermediates in the construction of DNA-encoded peptide libraries. Diverse amines were successfully converted into their corresponding thiopyrrole scaffolds, thereby expanding the structural diversity that can be achieved within DNA-encoded libraries.