CO2 as a traceless directing group for C-H functionalization

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Organic synthesis plays an essential role at the core of other disciplines, both in applied ones - such as drug discovery, or the development of new organic materials and sensors - and in more fundamental areas, such as chemical biology and the understanding of biological interactions at the molecular level. However, despite the many advances in our synthetic arsenal over the last century, this science is still limited in its ability to produce complex structures in an efficient way, hindering progress in all dependent disciplines. In 2009, these limitations were identified in the consultation conducted by the EPSRC, and 'Dial-a-Molecule - 100% efficient synthesis', as it was branded, has become one of the four Grand Challenges in chemical sciences and engineering. This Grand Challenge asks the question: how can we make molecules of interest in days instead of the currently needed years?Traditional synthetic strategies require the presence of reactive functional groups that are used as handles for further functionalization. This requirement is one of the factors dramatically enhancing the difficulty of syntheses. The last two decades have seen the emergence of a more straightforward alternative: the catalytic direct functionalization of C-H bonds. Through this strategy the typically inert C-H bonds, ubiquitous in organic molecules, can be activated by transition metal catalysts and subsequently functionalised. This approach has allowed us to dream of a future where any organic molecule could be synthesised in a direct manner by simply replacing the C-H bonds of a substrate with the required functionalities, as if building a ball-and-stick molecular model with our hands. The development of a full set of C-H functionalisation methodologies will impact on all applied areas, such as the synthesis of pharmaceuticals, agrochemicals, and new materials. Furthermore, their atom efficiency and low waste generation ensures a privileged position among the green chemistry methods.For this strategy to succeed, numerous challenges are still to be overcome. In this research proposal we aim at addressing one of them, called the 'regioselectivity of C-H activation problem': aromatic compounds generally contain many different C-H bonds, so how can chemists select (activate) just one of these bonds in the desired position? In our research we will develop a methodology capable of doing just that: 'selecting' one particular C-H bond in a series of aromatic compounds and transforming it into a different -desired- functionality.