Mechanical activation of a dithioester derivative-based retro RAFT-HDA reaction

A new mechanophore was synthesized from a dithioester derivative 1 and an open-chain diene 2 by the HDA reaction. It was embedded in the polymer chain by initiating the polymerization of methyl acrylate (MA). It was found that the PMA with M-n > 30 kDa could undergo a mechanically induced retro RAFT-HDA reaction rapidly at ambient temperature. The released species was evidenced chemically and spectroscopically, and the liberated dithioester derivative 1 maintained the activity to react with cyclopentadiene (Cp) or to copolymerize with styrene (St).