As with all things in life, necessity is the mother of invention. Synthetic chemistry, as an enabling science, will always rise to the challenge and meet the increasing demand for simpler and more efficient methods to construct fundamentally important structures and functional groups, particularly if these units are conserved privileged pharmacophores imparting biological activity to

This perspective article, from workers at Imperial College London and Pfizer, Cambridge, reviews the literature on site-selectivity in S-M coupling reactions for a wide variety of heterocycles on a case-by-case basis. It is shown that experimental parameters can critically impact the dominant catalytic species in solution and its ability to undergo the site-selectivity determining oxidative