Detailed Mechanistic Study of Radical Mediated Chemoselective Phosphination of Aryl Halide

Phosphines play important role in organic synthesis, since they are important ligands for transition metals catalysis. Moreover, phosphines are important building blocks of supramolecular architectures, and are used in advanced material sciences. An important reaction to make phosphines is the phosphination of organic halides. In this report, the mechanistic details of radical initiated phosphination of organic halides are studied theoretically for complete reaction cycle. The mechanistic studies are performed with an accurate method (ωB97XD), which we established for similar reactions through a benchmark study. The mechanistic studies are performed with aryl bromide and aryl iodide. The results show that overall reaction follows S_H2 pathway, and all steps are thermodynamically and kinetically favorable. The mechanistic outcomes of the research are in nice agreement with the recent experimental observations.