Screening method for the evaluation of asymmetric catalysts for the reduction of aliphatic ketones

Boukachabia, Mourad; Zeror, Saoussen; Collin, Jacqueline; Fiaud, Jean‐Claude; Aribi‐Zouioueche, Louisa

doi:10.1016/j.tetlet.2011.01.112

Cited by 30 publications

(18 citation statements)

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“…A substrate with an ester group 4 j could also be chemoselectively transformed into the desired alcohol in a favorable isolated yield and enantioselectivity (run 10). In addition, the oxo‐tethered Ru complexes were able to reduce aliphatic tert ‐butyl halomethyl ketones in good enantioselectivities of 50–70% (Table S1) …”

Section: Figurementioning

confidence: 99%

Selective Asymmetric Transfer Hydrogenation of α‐Substituted Acetophenones with Bifunctional Oxo‐Tethered Ruthenium(II) Catalysts

et al. 2017

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A practical method for the asymmetric transfer hydrogenation of a-substituted ketones was developed utilizing oxo-tethered N-sulfonyldiamine-ruthenium complexes. Reduction by HCO 2 H and HCO 2 K in a mixed solvent of EtOAc/H 2 O allowed for the selective synthesis of halohydrins from 2-bromoacetophenone (98%) and 2-chloroacetophenone (> 99%), leading to suppressed undesired side reactions stemming from formylation under the typical reaction conditions using an azeotropic 5:2 mixture of HCO 2 H and Et 3 N. A range of functional groups, such as halogens, methoxy, nitro, dimethylamino, and ester groups, were well tolerated, highlighting the potential of this method. Nearly complete selectivity with a preferable ee was maintained even with a substrate/ catalyst (S/C) ratio of 5000. This catalyst system was also effective for the asymmetric reduction of a-sulfonated ketones without eroding the leaving group.

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Section: Figurementioning

confidence: 99%

Selective Asymmetric Transfer Hydrogenation of α‐Substituted Acetophenones with Bifunctional Oxo‐Tethered Ruthenium(II) Catalysts

et al. 2017

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“…We obtained 2 octanol with 23% ee by Rh catalyzed asymmetric hydrogenation of 2 octanone in the presence of an inexpensive chiral ligand derived directly from L proline. 54 Preparation of monomer M12 from the 23% ee 2 octanol resulted in the formation of a mixture of (S,S) , (R,R) and meso isomers in a ratio of 38.8:15.8:45.4. The mixture of the stereoisomers as obtained was used in copolymerization with the phosphorus containing monomer to obtain PQXphos derived from (R) 2 octanol with 23% ee.…”

Section: Asymmetric Catalyses With Pqxphosmentioning

confidence: 99%

Poly(quinoxaline-2,3-diyl)s: A Fascinating Helical Macromolecular Scaffold for New Chiral Functions

Suginome

Yamamoto²,

Nagata³

2015

J. Synth. Org. Chem. Jpn.

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This paper is dedicated to late Prof. Yoshihiko Ito for his great enthusiasm and contribution to synthetic organic chemistry.Abstract: Studies on the synthesis, helical structure, switchable screw sense induction, catalytic function, and chiroptical properties of poly(quinoxaline 2,3 diyl)s since late 1980 s are described.1141 benzenes. Although there are some other options currently, in the typical procedure, the 3,6 substituted 1,2 phenylenediamines are treated with acetic formic anhydride to obtain the corresponding diformamides, which are subsequently dehydrated by phosgene dimer or POCl 3 in the presence of base, giving substituted 1,2 isocyanobenzanes in moderate to good yields (Scheme 2). 10 The obtained 3,6 substituted 1,2 diisocyanobenzenes are puri ed by column chromatography on silica gel and used in polymerization.Initial attempts at polymerization of those 1,2 diisocyanobenzenes are examined by using nucleophilic organometallic initiators. Reaction of 1,2 diisocyano 3,4,5,6 tetramethylbenzene (M1) in the presence of primary, secondary, and tertiary alkyl Grignard reagents (33 50 mol%) afforded quinoxaline dimer to hexamer in moderate yields (25 34% total isolated yields) (Scheme 3). 11This report was followed by the report on living polymerization of 1,2 diisocyanobenzene using an organopalladium complex as an initiator. 12 1,2 Diisocyanobenzene M1 was oligomerized with monomer/initiator ratios of 2, 3, 5, and 7 at re ux temperature in THF (Scheme 4). After oligomerization, the living palladium center was still at one of the two polymer terminus, being con rmed by isolation and single crystal X ray analysis of a terquinoxalinylpalladium complex. The living oligomers were quenched by Grignard reagents before isolation of the oligomers bearing an organic group derived from the Grignard reagent at the terminus. The degree of oligomerization was dependent on the monomer/initiator ratio with formation of up to octamer in good total yields. Application of this protocol to polymerization of 1,2 diisocyano 3,6 di(trimethylsilylmethyl)benzene (M2) afforded PQX with high molecular weight (M n 4830, vapor pressure osmometry (VPO)) with remarkably small PDI (polydispersity index, 1.08).In addition to the organopalladium complexes, it was also found that organonickel complexes served as highly active initiator in the polymerization of 1,2 diisocyanobenzenes (Scheme 5).13 Isolated 3 arylquinoxalin 2 ylnickel complex was used in the polymerization of 7 and 15 equivalents of M2, giving PQX in high yields with narrow PDI after quenching by Grignard reagents. It should be noted here that direct use of simple arylnickel(II) complex was not attempted in this report. Furthermore, use of Ni(acac) 2 , which is effective in the polymerization of monoisocyanides, was reported to form tarry material. More recently, it has been revealed that simpler nickel compounds including Ni(acac) 2 and NiCl 2 also give PQXs efciently albeit with large PDI (Scheme 6). 14 1,2 Diisocyanobenzene monomers bearing alkoxymethyl side chains was ...

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“…Asymmetric transfer hydrogenation of ketones has recently emerged as an alternative method for the production of chiral alcohols due to easy workup and availability of the reductants (Noyori & Hashiguchi 1997;Noyori & Ohkuma 2001;Palmer & Wills 1999;Gladiali & Alberico 2006;Samee et al 2006;Ikariya et al 2006). In this area, we have studied asymmetric transfer hydrogenation (ATH) of aromatic ketones in water using ruthenium-based catalysts (Zeror et al 2006(Zeror et al , 2008Boukachabia et al 2011). In the course of our previous investigations, the comparison between enantioselective bio-and metal-catalyzed reactions has been examined.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric reduction of ketones by biocatalysis using medlar (Mespilus germanicaL) fruit grown in Algeria

Bennamane

Zeror

Aribi‐Zouioueche

2014

Biocatalysis and Biotransformation

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The biocatalytic reduction of ketones was performed using medlar fruit (Mespilus germanica L) , which is grown in large amounts in Algeria. Experiments were performed using aqueous medium with fresh medlar. Prochiral heteroaryl ketones containing furan, thiophene, chroman, and thiochroman moieties were reduced with enantiomeric excess (ee) of up to 98%. High enantioselectivities have been observed especially for the bioreduction of tetralone 4 and thiochromanone 5 with ee of 89% and 98%, respectively. Bioreduction using different parts of medlar indicate that chromanone 6 was reduced with good asymmetric inductions 77% Ͻ ee Ͻ 85% whichever part of fruit was employed (whole, fl esh, or juice) and medlar juice exhibited the best activity.Biocatal Biotransformation Downloaded from informahealthcare.com by Monash University on 12/15/14For personal use only.

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Screening method for the evaluation of asymmetric catalysts for the reduction of aliphatic ketones

Cited by 30 publications

References 50 publications

Selective Asymmetric Transfer Hydrogenation of α‐Substituted Acetophenones with Bifunctional Oxo‐Tethered Ruthenium(II) Catalysts

Selective Asymmetric Transfer Hydrogenation of α‐Substituted Acetophenones with Bifunctional Oxo‐Tethered Ruthenium(II) Catalysts

Poly(quinoxaline-2,3-diyl)s: A Fascinating Helical Macromolecular Scaffold for New Chiral Functions

Asymmetric reduction of ketones by biocatalysis using medlar (Mespilus germanicaL) fruit grown in Algeria

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