Carbon-carbon (C-C) bonds make up the skeleton of all organic molecules. However, creating such ubiquitous C-C bonds artificially is still a complicated task. In particular, since several molecules used in medicine, pharmacology and material chemistry contain aryl groups, devising a way to efficiently and selectively introduce this chemical group is a major goal for organic chemists. Currently, most arylation reactions require harsh reaction conditions, including high temperatures and excess additives.
However, scientists devised a method to selectively introduce aryl groups into C-H bonds at room temperature. The study was performed by scientists at the Center for Catalytic Hydrocarbon Functionalization, within the Institute for Basic Science (IBS), South Korea, and published in Nature Chemistry.
The procedure consists of three main steps. Firstly, the iridium catalyst activates the C-H containing substrate. Secondly, arylsilane (aryl group) attacks the metal, creating an intermediate molecule. The team crystallized such intermediate and demonstrated that oxidizing the iridium centre of the intermediate (third step) is beneficial to achieve a low energy arylation reaction.
The proposed reaction mechanism was verified with electro-paramagnetic resonance, cyclic voltammetry and computer simulations.