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_NAr-halogenation, S_NAr-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.