Tetrafluorination of Aromatic Azide Yields a Highly Efficient Staudinger Reaction: Kinetics and Biolabeling

Abstract

The development of highly efficient bioorthogonal reactions is of paramount importance for the research fields of biomaterials and chemical biology. We found that the o,o'-difluorinated aromatic azide was able to react with triphenylphosphine to produce water-stable phosphanimine. To further improve the efficiency of this kind of nonhydrolysis Staudinger reaction, a tetrafluorinated aromatic azide was employed to develop a faster nonhydrolysis Staudinger reaction with a rate of up to 51 m s , as revealed by high-performance liquid chromatography (HPLC) analysis and fluorescence kinetics. As a proof-of-concept study, the highly efficient Staudinger reaction was successfully used for chemoselective fluorescence labeling of proteins and nucleic acids (DNA and RNA) as well as for protein polyethyleneglycol (PEG)ylation. We believe that this bioorthogonal reaction can provide a broadly useful tool for various bioconjugations.

Multifluorinated Aryl Azides for the Development of Improved H2S Probes, and Fast Strain‐promoted Azide‐Alkyne Cycloaddition and Staudinger Reactions

“…On the other hand, we as well as others have reported highly efficient NSR (Table 1) using o,o'-difluorinated and tetrafluorinated aryl azides since 2017. [26][27][28][29] Such NSR can be employed for fast chemical labeling of proteins, DNA and RNA. The improved SPAAC ligation based on multi-fluorinated aryl azides can be also a useful toolbox for bioconjugation.…”

“…[27] To this end, we designed and synthesized a linker 14 (Figure 8), which could be used for thiol-specific labeling via the maleimide moiety as well as fluorescence quenching because of the alkene moiety. [28] The reaction kinetics of the NSR could be monitored by a dansyl-dye conjugated triaryl phosphine 15 and 14 (Figure 8b). The reaction rate was determined as 51.8 M À 1 s À 1 , suggesting this is the fastest Staudinger ligation in aqueous buffer up to date.…”

“…The labeled efficiency for protein PEGylation was also high. [28] We proposed that this fast NSR can be generally useful toolbox for bioconjugation. It is noted that Hackenberger and co-workers reported Staudingerphosphite reactions for various bioconjugation applications, [41b-d] which could also be considered as NSR.…”

“…Consequently, a tetrafluorinated aryl azide was employed for development of a faster NSR . To this end, we designed and synthesized a linker 14 (Figure ), which could be used for thiol‐specific labeling via the maleimide moiety as well as fluorescence quenching because of the alkene moiety . The reaction kinetics of the NSR could be monitored by a dansyl‐dye conjugated triaryl phosphine 15 and 14 (Figure b).…”

“…In order to improve the reactivity of aryl azides, we as well as others have indicated that multifluorinated aryl azides could be used to significantly accelerate H 2 S-mediated reduction, SPAAC and Staudinger reactions. [25][26][27][28][29] In this minireview, we summarize the development and applications of these advanced bioorthogonal reactions based on multifluorinated aryl azides.…”