Sustainable synthesis of coumarins catalyzed by Au(I)/Au(III) complexes in ionic liquids

The possibility to directly activate C-H bonds is nowadays one of the most interesting perspectives, concerning the direct functionalization of organic substrates. Achieving a sufficient knowledge on the fundamental mechanisms that allow these transformations, will make possible to get access to new methodologies for more sustainable processes. Since the beginning of the new century, gold catalysis has received a lot of consideration in modern organometal-focused research environments. The strong affinity of gold for unsaturated organic systems opens a new avenue to explore as a potential tool for organic synthesis: the π-acid catalysis. This project deals with the activation of alkynes toward the hydroarylation reaction, performed by cationic Au(I)/Au(III) complexes. Moreover, the use of ionic liquids (ILs) as reaction media give us the possibility to explore a new and interesting catalytic system, which combines a positive solvent effect, enhancing the catalytic performance of the active species, with a sustainable choice. Indeed, ILs open a series of other features to be explored, such as the potential recyclability of the system, which constitutes a very attractive perspective to lower costs and process wastes, avoiding at the same time the use of conventional halogenated solvents (dichloromethane, dichloroethane). The process I have focused on, developed by the Applied Organometallic Chemistry group (DiSC- UNIPD, Prof. Biffis), has been applied for the synthesis of coumarins, organic products of interest for their bioactivity and optical properties. In collaboration with the LBPB group of Toulouse (LHFA-UPS, Prof. Bourissou), the potential application of (P,C)Au(III)X2 complexes has been also explored on this system, with the aim of expanding the reaction scope.