Achiral ruthenium catalyst encapsulated in titanium phosphonate homochiral peptide-based solids for enantioselective hydrogenation of ketones to secondary alcohols

Anat Milo, Ronny Neumann

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Asymmetric homogeneous catalysis is well established, but the design of new chiral catalysts and the optimization of an existing catalytic system are time- and manpower-exhausting processes. Desirable, heterogeneous, chiral analogues to facilitate catalyst recovery are relatively rare or function poorly. Here we further develop our strategy for facile adaptation of known reactions involving homogeneous achiral catalysts to those involving heterogeneous asymmetric catalysts by use of a homochiral solid scaffold and show the generality of this concept, from hydrolysis and oxidation reactions to hydrogenations. In this case, an inexpensive "off-the shelf" achiral hydrogenation catalyst, RuIICl2(R2PCH2CH2NH) 2, R = Ph, i-Pr, or t-Bu, embedded within a homochiral matrix is an enantioselective, recyclable heterogeneous catalyst for ketone hydrogenation. The amorphous matrix consists of tripodal poly(phenylglycine) capped with phosphonate moieties and cross-linked with titanium oxide. Hydrogenation of acetophenone derivatives can proceed with high enantioselectivity (up to 95% ee), and catalyst recycling by filtration is very effective.

Original languageEnglish
Pages (from-to)2531-2536
Number of pages6
JournalACS Catalysis
Volume2
Issue number12
DOIs
Publication statusPublished - Dec 7 2012

Fingerprint

Organophosphonates
Ruthenium
Titanium
Ketones
Peptides
Hydrogenation
Alcohols
Catalysts
Enantioselectivity
Titanium oxides
Scaffolds
Catalysis
Recycling
Hydrolysis
Derivatives
Recovery
Oxidation

Keywords

  • asymmetric catalysis
  • heterogeneous catalysis
  • hydrogenation
  • reduction of ketones
  • ruthenium

ASJC Scopus subject areas

  • Catalysis

Cite this

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AU - Milo, Anat

AU - Neumann, Ronny

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Y1 - 2012/12/7

N2 - Asymmetric homogeneous catalysis is well established, but the design of new chiral catalysts and the optimization of an existing catalytic system are time- and manpower-exhausting processes. Desirable, heterogeneous, chiral analogues to facilitate catalyst recovery are relatively rare or function poorly. Here we further develop our strategy for facile adaptation of known reactions involving homogeneous achiral catalysts to those involving heterogeneous asymmetric catalysts by use of a homochiral solid scaffold and show the generality of this concept, from hydrolysis and oxidation reactions to hydrogenations. In this case, an inexpensive "off-the shelf" achiral hydrogenation catalyst, RuIICl2(R2PCH2CH2NH) 2, R = Ph, i-Pr, or t-Bu, embedded within a homochiral matrix is an enantioselective, recyclable heterogeneous catalyst for ketone hydrogenation. The amorphous matrix consists of tripodal poly(phenylglycine) capped with phosphonate moieties and cross-linked with titanium oxide. Hydrogenation of acetophenone derivatives can proceed with high enantioselectivity (up to 95% ee), and catalyst recycling by filtration is very effective.

AB - Asymmetric homogeneous catalysis is well established, but the design of new chiral catalysts and the optimization of an existing catalytic system are time- and manpower-exhausting processes. Desirable, heterogeneous, chiral analogues to facilitate catalyst recovery are relatively rare or function poorly. Here we further develop our strategy for facile adaptation of known reactions involving homogeneous achiral catalysts to those involving heterogeneous asymmetric catalysts by use of a homochiral solid scaffold and show the generality of this concept, from hydrolysis and oxidation reactions to hydrogenations. In this case, an inexpensive "off-the shelf" achiral hydrogenation catalyst, RuIICl2(R2PCH2CH2NH) 2, R = Ph, i-Pr, or t-Bu, embedded within a homochiral matrix is an enantioselective, recyclable heterogeneous catalyst for ketone hydrogenation. The amorphous matrix consists of tripodal poly(phenylglycine) capped with phosphonate moieties and cross-linked with titanium oxide. Hydrogenation of acetophenone derivatives can proceed with high enantioselectivity (up to 95% ee), and catalyst recycling by filtration is very effective.

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