Triple C-H Activation/Annulation: In Situ Construction of Fluorescent Peptides
Zhefan Zhang1, Tianyan Wan2, Qi Quan1
1Jiangsu Provincial Key Lab for the Chemistry and Utilization of Agro-Forest Biomass, Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab of Biomass-Based Green Fuels and Chemicals, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu, China.
Abstract:
Herein, we report a Rh(III)-catalyzed triple C-H activation-annulation of Phe-based peptides with alkynes for the preparation of fluorescent peptides. The robustness of this protocol is reflected by a broad substrate scope, high atom- and step-economy, and excellent chemo- and site-selectivity. An in situ generated polycyclic aromatic hydrocarbon carbocation as a fluorophore exhibits good fluorescence properties (maximum emission wavelength up to 628 nm) and low cell cytotoxicity. The synthetic utility of this method is further demonstrated by versatile product applications in bioconjugation with the protein BSA and specifically targeting lysosomes and mitochondria of live mammalian cells.
