Hydrogenation of 1-phenyl-1,2-propanedione over Pt catalysts modified by cinchona alkaloid O-ethers and the kinetic resolution of the 1-hydroxyketones generated

I Busygin, Johan Wärnå, E Toukoniitty, Dmitry Murzin, Reko Leino

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

18 Citeringar (Scopus)

Sammanfattning

Nine cinchona alkaloid O-ethers together with cinchonidine and cinchonine were studied as chiral modifiers in the enantioselective hydrogenation of 1-phenyl-1,2-propanedione over Pt/Al(2)O3. The influence of the O-substituent on the reaction rate, selectivity and product distribution was investigated. Apparent rate constants for all hydrogenation steps were calculated using a first-order kinetic approach resulting in a good agreement between the experimentally recorded and predicted concentrations. The experimentally observed structure-selectivity effects indicate that the mechanisms of enantiodifferentiation over the catalyst modified by parent cinchona alkaloids and their ether derivatives differ from each other. Moreover, the modifier structure-selectivity dependence and the solvent effect were different for enantio- and diastereoselection in the 1-phenyl-1,2-propanedione and 1-hydroxyketone hydrogenations. Correlation between the modifier substituent bulkiness and diastereoselectivity of the 1-hydroxyketone hydrogenation was observed. Data on the inversion of enantioselectivity of 1-phenyl-1,2-propanedione hydrogenation, diastereoselectivity and the sense of kinetic resolution of the 1-hydroxyketones were presented. Due to the complexity of the reaction network, several competing mechanistic pathways may be present in a single reaction system. (C) 2008 Elsevier Inc. All rights reserved.
OriginalspråkOdefinierat/okänt
Sidor (från-till)339–348
Antal sidor10
TidskriftJournal of Catalysis
Volym254
Utgåva2
DOI
StatusPublicerad - 2008
MoE-publikationstypA1 Tidskriftsartikel-refererad

Nyckelord

  • 1-phenyl-1,2-propanedione
  • cinchona alkaloids
  • heterogeneous catalysis
  • hydrogenation kinetics
  • inversion of diastereoselectivity
  • inversion of enantioselectivity

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