This paper explores photoswitchable reversible covalent conjugate addition-elimination reactions for light-addressed modular covalent connection and disconnection. By coupling a photochromic dithienylethene (DTE) switch with Michael acceptors, the reactivity of Michael reactions is tuned, allowing switching on and off dynamic exchange of thiol and amine nucleophiles. The change in antiaromaticity in transition states and enol intermediates drives the photoinduced change in kinetic barriers. Applications demonstrated include light-mediated surface modification, regulation of amphiphilic assemblies, and on-demand creation/degradation of covalent polymers.

Hanwei Lu, Hebo Ye, Meilan Zhang, Zimu Liu, Hanxun Zou, Lei You