Fluorogenic Protein Labeling by Generation of Fluorescent Quinoliziniums Using [Cp*RhCl₂]₂

Abstract

Fluorogenic labeling has received considerable attention as a result of the high demand in chemical biology and synthetic biology applications. Herein, we develop a new strategy for fluorescent turn-on ligation targeting alkyne- and quinoline-linked peptides and proteins (λem of 515 nm and up to ΦF of 0.20) using the [Cp*RhCl2]2 catalyst. The good conversion, high flexibility, broad utility, ease of use, and mild reaction conditions are great advantages to extend the rhodium-mediated turn-on fluorogenic bioconjugation for further applications.

Fluorogenic Reactions in Chemical Biology: Seeing Chemistry in Cells

“…(c) Synthesis of quinolizinium-labeled lysozyme ( 6 - 10 and 6 - 13 ) through two different pathways. Adapted with permission from ref . Copyright 2022 American Chemical Society.…”

“…In 2022, Wong et al 130 developed a strategy for fluorescent turn-on ligation targeting alkyne-and quinoline-linked peptides and proteins using the [Cp*RhCl 2 ] 2 catalyst. This bioconjugation strategy provided stable fluorescent quinoliziniums under mild reaction conditions with good to excellent conversion.…”

Copper-Catalyzed Cyclization of 2-Alkynylanilines to Give 2-Haloalkoxy-3-alkyl(aryl)quinolines

“…As a critical, widely available feedstock, 2-alkoxyquinolines are fundamental to the preparation of pharmaceuticals and biologically active molecules, efficient catalysts, ligands, and fluorescent and phosphorescent probe molecules. In particular, 2-haloalkoxyquinolines are elementary synthetic building blocks and basic bioactive skeletons that widely exist in bioactive medicine (Figure ).…”