Sueur B, Leclercq L, Sauthier M, Castanet Y, Mortreux A, Bricout H, Tilloy S, Monflier E. Rhodium Complexes Non-Covalently Bound to Cyclodextrins: Novel Water-Soluble Supramolecular Catalysts for the Biphasic Hydroformylation of Higher Olefins.
Chemistry 2005;
11:6228-36. [PMID:
16075437 DOI:
10.1002/chem.200500337]
[Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A new class of cationic alpha-cyclodextrins bearing 2-hydroxy-3-trimethylammoniopropyl groups has been synthesised. We investigated their efficiency as mass-transfer promoters in a biphasic hydroformylation reaction catalysed by a rhodium trisulfonated triphenylphosphine system. These cationic alpha-cyclodextrins greatly increased the reaction rate, the chemoselectivity, and, surprisingly, the linear-to-branched aldehyde ratio. We attributed this unexpected enhancement of the linear-to-branched aldehyde ratio to the in situ formation of new catalytic supramolecular species obtained by ion-exchange between the catalyst ligand and the cationic alpha-cyclodextrins.
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