A Broadly Applicable Strategy to Aminate Azines Enabled by Electronically Tuned Phosphine Reagents

We describe a strategy for aminating pyridines and other azines via phosphonium salt intermediates. Precisely tuning the electronic properties of the phosphonium ion was key for C─N bond formation via an S N Ar‐halogenation, S N Ar‐amination sequence. The process couples a wide range of amine classes with pyridines and is viable for applications such as late‐stage amination of complex pharmaceuticals and fragment–fragment coupling reactions. The capacity to rapidly modify the structure of the phosphine reagent was decisive and is a valuable feature in pseudohalide design.