Catalytic deoxygenation of 1,2-propanediol to give n-propanol

Marcel Schlaf, Prasenjit Ghosh, Paul J. Fagan, Elisabeth Hauptman, R. Morris Bullock

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

Deoxygenation of 1,2-propanediol (1.0M in sulfolane) catalyzed by bis(dicarbonyl)(μhydrido)(pentamethylcyclopentadiene)ruthenium trifluoromethanesulfonate ({[Cp*Ru(CO)2]2(μ.-H)} +OTf-) (0.5 mol%) at 110°C under hydrogen (750 psi) in the presence of trifluoromethanesulfonic acid (HOTf) (60 mM) gives n-propanol as the major product, indicating high selectivity for deoxygenation of the internal hydroxy group over the terminal hydroxy group of the diol. The deoxygenation of 1,2-propanediol is strongly influenced by the concentration of acid, giving faster rates and proceeding to higher conversions as the concentration of HOTf is increased. Propionaldehyde was observed as an intermediate, being formed through acid-catalyzed dehydration of 1,2-propanediol. This aldehyde is hydrogenated to n-propanol through an ionic pathway involving protonation of the aldehyde, followed by hydride transfer from the neutral hydride, dicarbonyl(pentamethylcyclopentadiene)ruthenium hydride [Cp*Ru(CO)2H]. The proposed mechanism for the deoxygenation/hydrogenation reaction involves formation of a highly acidic dihydrogen complex [Cp*Ru(CO)22-H 2)]+ OTf-.

Original languageEnglish
Pages (from-to)789-800
Number of pages12
JournalAdvanced Synthesis and Catalysis
Volume351
Issue number5
DOIs
Publication statusPublished - Mar 1 2009

Keywords

  • Deoxygenation
  • Dihydrogen complexes
  • Heterolytic reaction
  • Homogeneous catalysis
  • Metal hydrides
  • Ruthenium

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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