Mechanically Triggered Small Molecule Release from a Masked Furfuryl Carbonate

Stimuli-responsive polymers that
release small molecules under
mechanical stress are appealing targets for applications ranging from
drug delivery to sensing. Here, we describe a modular mechanophore
design platform for molecular release via a mechanically triggered
cascade reaction. Mechanochemical activation of a furan–maleimide
Diels–Alder adduct reveals a latent furfuryl carbonate that
subsequently decomposes under mild conditions to release a covalently
bound cargo molecule. The computationally guided design of a reactive
secondary furfuryl carbonate enables the decomposition and release
to proceed quickly at room temperature after unmasking via mechanical
force. This general strategy is demonstrated using ultrasound-induced
mechanical activation to release a fluorogenic coumarin payload from
a polymer incorporating a chain-centered mechanophore.