Prins cyclization of (-)-isopulegol with benzaldehyde for production of chromenols over organosulfonic clays

Nikolai Li-Zhulanov, Päivi Mäki-Arvela, Mathias Laluc, Andreia F. Peixoto, Ekaterina Kholkina, Thomas Sandberg, Atte Aho, Konstantin Volcho, Nariman Salakhutdinov, Cristina Freire, Alexander Yu. Sidorenko, Dmitry Murzin

    Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

    6 Citeringar (Scopus)

    Sammanfattning

    Prins cyclization of (-)-isopulegol with benzaldehyde was investigated with sulphur containing halloysite nanotubes, K10 clays and Cloisite clays. The catalysts were characterized by TEM, SEM, XRD, XPS, pyridine adsorption desorption by FTIR, nitrogen adsorption. The most active catalyst was K10 modified with chlorosulphonic acid giving 95% selectivity to the desired chromenol at 90% conversion and 30 degrees C. Selectivity to chromenol was increasing with increasing Lewis acid site concentration while no linear correlation of chromenol selectivity with the Bronsted acid sites concentration was observed. The diastereoisomer R/S ratio of chromenols was the highest, 11.5, at 70 degrees C and 90% conversion over sulphur modified halloysite nanotubes exhibiting rather low acidity. A higher stability of the R-isomer confirmed by quantum mechanical calculations can partially explain preferential formation of the R diastereomer.Successful catalyst reuse was demonstrated with the best performing catalyst, organosilylated sulphur containing K10.
    OriginalspråkOdefinierat/okänt
    Sidor (från-till)
    Antal sidor12
    TidskriftMolecular Catalysis
    Volym478
    DOI
    StatusPublicerad - 2019
    MoE-publikationstypA1 Tidskriftsartikel-refererad

    Nyckelord

    • Isopulegol
    • Organosulfonic clays
    • Prins reaction
    • Chromenols

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