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 SNAr-halogenation, SNAr-amination sequence. The process accommodates a wide range of amine classes and pyridine coupling partners 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.