111316-10-0Relevant articles and documents
Sterically Shielded, Stabilized Nitrile Imine for Rapid Bioorthogonal Protein Labeling in Live Cells
An, Peng,Lewandowski, Tracey M.,Erbay, Tug?e G.,Liu, Peng,Lin, Qing
supporting information, p. 4860 - 4868 (2018/04/16)
In pursuit of fast bioorthogonal reactions, reactive moieties have been increasingly employed for selective labeling of biomolecules in living systems, posing a challenge in attaining reactivity without sacrificing selectivity. To address this challenge, here we report a bioinspired strategy in which molecular shape controls the selectivity of a transient, highly reactive nitrile imine dipole. By tuning the shape of structural pendants attached to the ortho position of the N-aryl ring of diaryltetrazoles-precursors of nitrile imines, we discovered a sterically shielded nitrile imine that favors the 1,3-dipolar cycloaddition over the competing nucleophilic addition. The photogenerated nitrile imine exhibits an extraordinarily long half-life of 102 s in aqueous medium, owing to its unique molecular shape that hinders the approach of a nucleophile as shown by DFT calculations. The utility of this sterically shielded nitrile imine in rapid (～1 min) bioorthogonal labeling of glucagon receptor in live mammalian cells was demonstrated.
