The covalent immobilization of the biomimetic, photo-organocatalyst (-)-riboflavin on silica micro- and nanoparticles via atom transfer radical polymerization (ATRP) is disclosed. Given the effectiveness of (-)-riboflavin as a versatile, environmentally benign photocatalyst, an immobilization strategy based on acrylate-linker modification of the catalyst core and controlled polymerization on initiator pre-functionalized silica particles has been developed. Validation of this approach is demonstrated in the E→Z isomerization of a benchmark cinnamonitrile (Z/E up to 88:12) with 0.97 mol % catalyst loading. Characterization of the immobilized photocatalyst supports covalent embedding of the catalyst in the polymeric brushes on the silica particle surface.

Fluorinated acyl‐Meldrum's acid derivatives were synthesized by electrophilic fluorination of appropriate phenacyl Meldrum's acid substrates using Selectfluor. Reactions with water, ethanol, Grignard, and alkynyllithium reagents gave rise to the corresponding fluoro‐acetophenone, –1,3‐keto ester, –1,3‐diketone and ‐pyran‐4‐one products respectively from the same selectively fluorinated scaffold in one‐step procedures.

The reported immobilization strategy for the riboflavin photocatalyst as a lasso catching the catalyst is depicted in the frontispiece. The lasso is held by silica “cowboy” particles, and the sand of the desert reinforces the silica theme. The sun conveys that light irradiation is necessary for the isomerization reaction. For more information see the Communication by B. J. Ravoo, R. Gilmour, et al. on page 4228 ff.