Fast Alkene Functionalization In Vivo by Photoclick Chemistry: HOMO Lifting of Nitrile Imine Dipoles

Abstract
Extremely fast fluorescence labeling (Escherichia coli cells was observed with tetrazole 1. The electron‐donating methoxy substituent raises the energy of the highest occupied molecular orbital of the nitrile–imine intermediate derived from 1. This strategy greatly accelerates the functionalization of alkenes by 1,3‐dipolar cycloaddition in living systems. magnified image