Dual-Wavelength Gated -Diels-Alder Photoligation.

The control of chemical functionalization with orthogonal light stimuli paves the way toward manipulating materials with unprecedented spatiotemporal resolution. To reach this goal, we herein introduce a photochemical reaction system that enables two-color control of covalent ligation via an -Diels-Alder cycloaddition between two separate light-responsive molecular entities: a UV-activated photocaged diene based on -quinodimethanes and a carbonyl dienophile appended to a diarylethene photoswitch, whose reactivity can be modulated upon illumination with UV and visible light.