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"Lewis Acidic Borocations: improving Suzuki couplings, Material synthesis, Alkylation and Radical Transformations" (LAB-SMART)
Date du début: 1 oct. 2012, Date de fin: 30 sept. 2017 PROJET  TERMINÉ 

"Carbon-carbon bond formation is arguably the most important reaction in synthetic chemistry, exemplified by the award of five noble prizes. The most recent Nobel prize was awarded for the development of palladium catalysed cross coupling, of which Suzuki cross coupling is the most widely applied version in industry and academia and utilizes organo-boronates (RB(OR)2) as the nucleophilic component. The aims of this project are; (i) to simplify the synthesis of organo-boron compounds that are utilized in (a) Suzuki cross coupling and (b) as boron containing materials for organic electronic applications. (ii) Reduce the dependency on expensive and toxic palladium by a) extending the Friedel Crafts C-C bond forming reaction to broad scope, electrophilic trifluoromethylation and electrophilic arylation (b) generating and applying efficient iron catalysts in an iron analogue of the Suzuki Reaction.To achieve each of our aims we will utilise the unique properties of electrophilic borocations. Previously we have used boro-cations that combine a coordinatively unsaturated and electrophilic boron centre with a ‘masked’ form of a strong base to develop fundamentally new reactivity. These borocations enabled the sequential one pot activation of a substrate by a strong Lewis acid (the boro-cation) and then release of the masked Lewis base for a subsequent step (e.g., deprotonation). This concept of a boron reagent enabling sequential reactivity by subsequent dissociation of a group is a continual theme through this proposal. This property of borocations will be combined with appropriate leaving groups on the nucleophile to tackle the important challenges outlined above. Key to expanding the synthetic utility is design of the borocation to enable the release not only of a neutral Lewis base (for direct borylation, including the synthesis of RB(OR)2) but also an anionic group (for arylation/alkenylation) or a cationic moiety (for alkylation)."