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Rhodium-catalyzed alkene and alkyne hydroacylation (HYDROACYLATION)
Date du début: 15 oct. 2013, Date de fin: 14 oct. 2015 PROJET  TERMINÉ 

The hydroacylation reaction (HA) is a potentially powerful transformation in organic synthesis. The transformation of an aldehyde and an unsaturated hydrocarbon into a ketone involves the formation of a new C-C bond under atom-economical conditions. The main limitation of this reaction is the possible decarbonylation of one of the reaction intermediates. This research proposal aims the control of this undesirable decarbonylation pathway. This will be achieved by both attenuating decarbonylation and promoting the (rate limiting) reductive elimination step of the final product. With this in mind and taking into account the results recently reported by the host laboratory in the HA field (J. Am. Chem. Soc., 2012, 134, 4885), a new generation of Rh(I) complexes containing small bite angle diphosphine ligands will be employed.The preparation of a series of small bite angle PXP ligands (X being C, N or B) would allow the study of the effect of the different steric and electronic parameters on the catalytic performance of the Rh(I) complexes. Metal complexes bearing phosphine ligands with different R groups (iPr, tBu, Cy, Ph, etc.), hemilabile phosphine ligands and ligands with suitable hydrophilic functionalities (water-soluble R groups) will be screened under the standard “challenging” HA conditions.This project will deliver the synthesis of a set general intermolecular HA catalysts that demonstrate high levels of functional group tolerance, stability under catalytic conditions, attractive rates of reaction for demanding substrates, low catalyst loadings with use of minimal and green solvents. By achieving this, we believe that HA will become a general and robust synthetic method for the production of fine and bulk chemicals, new materials and target molecules, rivaling the process of metathesis, hydrogenation, C–C cross coupling and alkene oxidation that are primary disconnections in organic synthetic methodology.