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  • Highly Efficient Rhodium Ca...
    Gual, Aitor; Godard, Cyril; Castillón, Sergio; Claver, Carmen

    Advanced synthesis & catalysis, 02/2010, Letnik: 352, Številka: 2-3
    Journal Article

    Abstract Here, we describe the successful application of novel glucofuranose‐derived 1,3‐diphosphites in the rhodium‐catalysed asymmetric hydroformylation of vinyl acetate, 2,5‐dihydrofuran and 2,3‐dihydrofuran. In the hydroformylation of vinyl acetate, total regioselectivity and high ee (up to 73%) were obtained. When 2,3‐ and 2,5‐dihydrofuran were the substrates, total chemo‐ and regioselectivities were achieved together with ee s up to 88%. These results correspond to the highest ee values reported to date in the asymmetric hydroformylation of these substrates. The HP‐NMR studies of the RhH(CO) 2 (L) species (L= 15 and 17 ) demonstrated that both ligands coordinate to the Rh centre in an eq‐eq fashion. The complex RhH(CO) 2 ( 15 ) was detected as a single isomer with characteristic features of eq‐eq coordination. However, the broadening of the corresponding signals indicated that this species is rapidly interchanging in solution. In contrast, complex RhH(CO) 2 ( 17 ) was detected as a mixture of two conformational isomers at low temperature due to the greater flexibility of the monocyclic backbone of this ligand.