Synthesis of Amino Acid α-Thioethers and Late-Stage Incorporation into Peptides.

The accelerating discovery of structurally distinct peptide natural products bearing α-thioether cross-links, such as the family of sactipeptide natural products, highlights the need for strategies to synthesize this underexplored functional motif. Herein, we describe the preparation of orthogonally protected, cross-linked amino acid α-thioether building blocks and probe their stability toward conventional solid-phase peptide synthesis. We overcome challenges with linkage lability by developing a late-stage, on-resin approach to α-thioethers, providing important proof-of-principle for sactipeptide synthesis.

Polymer End Group Control through a Decarboxylative Cobalt-Mediated Radical Polymerization: New Avenues for Synthesizing Peptide, Protein, and Nanomaterial Conjugates.

Cobalt-mediated radical polymerizations (CMRPs) have been initiated by the radical decarboxylation of tetrachlorophthalimide activated esters. This allows for the controlled radical polymerization of activated monomers across a broad temperature range with a single cobalt species, with the incorporation of polymer end groups derived from simple carboxylic acid derivatives and termination with an organozinc reagent. This method has been applied to the synthesis of a polymer/graphene conjugate and a water-soluble protein/polymer conjugate, demonstrating the first examples of CMRP in graphene and protein conjugation.