Solid-Phase Synthesis of Iterative RAFT Single Unit Monomer Insertion Adducts

In this communication, we disclose the use of a solid-phase methodology to synthesize iterative RAFT single unit mono-mer insertion (SUMI) adducts. This methodology features a reversible thiocarbonylthio protecting group and radical chain growth of vinyl monomers, with minimal purification required during the synthesis. To achieve this, a RAFT chain transfer agent was immobilized on a common peptide synthesis resin via the “R-group” in the first instance. Using an ox-ygen-tolerant PET-RAFT methodology, we then extended the iterative synthesis of sequence-defined indene-maleimide alternating co-oligomers to 18 units with minimal dispersity, completely unprecedented in SUMI chemistry. Furthermore, as we demonstrate, this solid-phase methodology can be generalized to other maleimide derivatives and other solid-phase resins.