Investigation into the enantioselection mechanism of ruthenium–arene–diamine transfer hydrogenation catalysts using fluorinated substrates

Slungård, Sigrid Volden; Krakeli, Tor-Arne; Thvedt, Thor Håkon Krane; Fuglseth, Erik; Sundby, Eirik; Hoff, Bård Helge

doi:10.1016/j.tet.2011.05.099

Cited by 37 publications

(17 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alcohol 29 was formed in very low ee of only 8% (>99% conversion) at S/C 500, although this could be raised to 20% ee (R using (S,S)-7) at S/C 50. 11 In contrast the reduction of 1,1,1-trifluoroacetone resulted in formation of 30 in 94% ee ((S)-product formed using (S,S)-7). 1,1,1-Trifluoro-2-propanol 30 is an important chiral building block difficult to access due to its tendency to form self-condensation side-products.…”

Section: Resultsmentioning

confidence: 98%

“…The low ee for the formation of 29 would suggest that the Ph and CF3 groups have similar affinity for the ruthenium-bound  6 arene within the accepted transition states for ketone reductions by these compounds, 7 whilst the high ee and sense of reduction to give 30 indicates that the CF3 has a higher affinity than the methyl group, as would be anticipated. 11 During the reduction of 1,1,1-trifluoroacetone, a side product, which may be the product of addition of methanol to the substrate, was observed along with incomplete conversion. Addition of ca 10 mol% of water resulted in full reduction to 30, possibly due to reversal of formation of the observed side product.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Application of Tethered Ruthenium Catalysts to Asymmetric Hydrogenation of Ketones, and the Selective Hydrogenation of Aldehydes

et al. 2012

View full text Add to dashboard Cite

, 1974-and Wills, Martin. (2012 Application of tethered ruthenium catalysts to asymmetric hydrogenation of ketones, and the selective Hydrogenation of aldehydes. Advanced Synthesis & Catalysis, 354 (13). pp. 2545-2555. Permanent WRAP url:http://wrap.warwick.ac.uk/55017 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available. Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Abstract. An improved method for the synthesis of tethered ruthenium(II) complexes of monosulfonylated diamines is described, together with their application to hydrogenation of ketones and aldehydes. The complexes were applied directly, in their chloride form, to asymmetric ketone hydrogenation, to give products in excess of 99% ee in the best cases, using 30 bar of hydrogen at 60 °C , and to the selective reduction of aldehydes over other functional groups.

show abstract

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Application of Tethered Ruthenium Catalysts to Asymmetric Hydrogenation of Ketones, and the Selective Hydrogenation of Aldehydes

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Thus, the face that was attacked is the opposite to that of other ketones because of the inversion of priority due to the presence of the CF 3 group. The loss of enantiomeric induction with CF 3 compared with CH 3 has previously been observed in the reduction with [RuCl( p ‐cymene){( R , R )‐TsDPEN}] and has been attributed to an attack at the opposite side due to a poor size differentiation between CF 3 and the phenyl core 29. Finally, dialkyl ketones underwent moderate conversion and with low enantiomeric excess (Scheme , products 7 and 8 ).…”

Section: Resultsmentioning

confidence: 74%

Biphasic Glycerol/2‐MeTHF, Ruthenium‐Catalysed Enantioselective Transfer Hydrogenation of Ketones Using Sodium Hypophosphite as Hydrogen Donor

et al. 2013

View full text Add to dashboard Cite

Sodium hypophosphite has been used as an efficient hydrogen donor in the transfer hydrogenation of aliphatic and aromatic ketones in the presence of [RuCl2(p‐cymene)]2 and 2,2′‐bipyridine in water. The corresponding alcohols were isolated in moderate to excellent yields (39–95 %). Good chemoselectivity was observed with ester, nitrile and halide functionalities in the ketones not being reduced. An enantioselective version of the reaction using [RuCl(p‐cymene){(R,R)‐TsDPEN}] as catalyst in a glycerol/2‐MeTHF biphasic solvent mixture has been developed and allowed the reduction of (hetero)aromatic ketones with excellent chemo‐ and enantioselectivities (up to 97 % ee).

show abstract

“…Indeed, perfluoroalkyl ketones are known as low‐ yielding substrates in classical asymmetric hydrogenation protocols. Not surprisingly, optimized catalytic systems for acetophenones do not proceed efficiently for trifluoroacetophenones and suffer from poor enantioselectivities due to their vastly different stereoelectronic properties . In this work, we address this challenge by presenting an efficient protocol for the asymmetric hydrogenation of aryl perfluoroalkyl ketones using rhodium(III) complexes bearing Josiphos‐type ligands (Scheme ).…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands

Brüning

Nagae

Käch

et al. 2019

Chemistry A European J

View full text Add to dashboard Cite

The asymmetric hydrogenation of 2,2,2‐trifluoroacetophenones and aryl perfluoroalkyl ketones was developed using a unique, well‐defined chloride‐bridged dinuclear rhodium(III) complex bearing Josiphos‐type diphosphine ligands. These complexes were prepared from [RhCl(cod)]2, Josiphos ligands, and hydrochloric acid. As catalyst precursors, they allow for the efficient and enantioselective synthesis (up to 99 % ee) of chiral secondary alcohols with perfluoroalkyl groups. This system does not require an activating base for the hydrogenation of 2,2,2‐trifluoroacetophenones. Additionally, the enantioselective C=O hydrogenations of 2‐phenyl‐3‐(haloacetyl)‐indoles, a class of privileged structures in medicinal chemistry, is reported for the first time.

show abstract

Investigation into the enantioselection mechanism of ruthenium–arene–diamine transfer hydrogenation catalysts using fluorinated substrates

Cited by 37 publications

References 50 publications

Application of Tethered Ruthenium Catalysts to Asymmetric Hydrogenation of Ketones, and the Selective Hydrogenation of Aldehydes

Application of Tethered Ruthenium Catalysts to Asymmetric Hydrogenation of Ketones, and the Selective Hydrogenation of Aldehydes

Biphasic Glycerol/2‐MeTHF, Ruthenium‐Catalysed Enantioselective Transfer Hydrogenation of Ketones Using Sodium Hypophosphite as Hydrogen Donor

Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands

Contact Info

Product

Resources

About