Novel fluorous prolinol as a pre-catalyst for catalytic asymmetric borane reduction of various ketones

Goushi, Sakiko; Funabiki, Kazumasa; Ohta, Masaya; Hatano, K.; Matsui, Masaki

doi:10.1016/j.tet.2007.02.117

Cited by 40 publications

(14 citation statements)

References 24 publications

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“…ATH of the 1-naphthyl ketones 8e12 using catalyst I and III, R¼CH 3 (8,20), CH 2 F (9, 21), CHF 2 (10,22), CF 3 (11,23), CH 2 CH 3 (12,24). Table 3 ATH of 1aeg, 2aeg and 4aee to the alcohols 13aeg, 14aeg and 16aee using catalyst I and III in formic acid/triethylamine: ee (%), conversion (conv.)…”

Section: -12 20-24mentioning

confidence: 99%

“…15,27 4.5.1. (S)-2,2-Difluoro-1-phenylethanol (15b) 21,23 . The reaction was performed starting with [RuCl 2 (mesitylene)] 2 (12 mg, 0.02 mmol), TsDPEN (22 mg, 0.06 mmol) and 2,2,-difluoro-1-phenylethanone (3b) (312 mg, 2.00 mmol) in formic acid/NEt 3 (5/2 mol ratio, 45 .…”

Section: Reference Materialsmentioning

confidence: 99%

“…16,17 Although useful protocols exist for the asymmetric reduction of 1-aryl-2,2-difluoroethanones and 1-aryl-2,2,2-trifluoroethanones, 18e22 asymmetric reduction of the such fluoroketones often gives the product alcohols in mediocre ee. 16e18, 23,24 Thus, increased knowledge of the effects caused by fluorine in asymmetric processes is needed.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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Section: -12 20-24mentioning

confidence: 99%

Section: Reference Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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“…These shortcomings have been addressed using fluorous tags, [22][23][24][25] magnetically recoverable 26 or ionic liquid based catalysts. 27 Alternatively, the chiral unit can be covalently immobilised on an insoluble carrier matrix.…”

Section: O M / L O C a T E / T E T A S Ymentioning

confidence: 99%

“…24 The drawback of the method is that the exotic HFE-7500 solvent has to be used. Catalyst IX, 22 with a straight chain fluorous tag, was tested in refluxing toluene (10 mol %). The selectivites were slightly lower than in the case of VIII.…”

Section: 45mentioning

confidence: 99%

Enantioselectivity, swelling and stability of 4-hydroxyprolinol containing acrylic polymer beads in the asymmetric reduction of ketones

Thvedt¹,

Kristensen²,

Sundby³

et al. 2011

Tetrahedron: Asymmetry

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a b s t r a c tA new 4-hydroxy-a,a-diphenyl-L-prolinol containing polymethacrylate, prepared without chromatography by a large scale adaptable synthesis, has been evaluated as a catalyst in the asymmetric reduction of 1-arylethanones. Using 1-(4-bromophenyl)ethanone as the model substance, the reduction was tested with various borane sources and solvents. The best swellings of the polymer and reactivity were observed in THF using N,N-diethylaniline borane complex as the hydride source. The selectivity in the reduction of 1-(4-bromophenyl)ethanone was found to depend on the substrate concentration and catalyst loading. Using the best conditions identified, a series of 1-arylethanones was reduced to their corresponding enantioenriched secondary alcohols. High rates and ee-values were obtained in the reduction of acetophenones containing electron withdrawing groups in the aromatic ring, whereas a moderate selectivity was the result for products containing electron donating aromatic substituents. Upon recovery of the polymer beads, it was found that vacuum drying led to extensive rupturing, while the bead structure was intact if washed with methanol and air dried at atmospheric pressure. Repeated use of the polymer catalyst gave the product alcohol with a lower 90% ee. Elemental analysis showed this to be due to the loss of the chiral prolinol unit.

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Fluorous Chiral Catalyst Immobilization

Soós¹

2009

Recoverable and Recyclable Catalysts

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Novel fluorous prolinol as a pre-catalyst for catalytic asymmetric borane reduction of various ketones

Cited by 40 publications

References 24 publications

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

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

Enantioselectivity, swelling and stability of 4-hydroxyprolinol containing acrylic polymer beads in the asymmetric reduction of ketones

Fluorous Chiral Catalyst Immobilization

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