Synthesis of (R)-tembamide and (R)-aegeline via asymmetric transfer hydrogenation in water

Cortez, Norma A.; Aguirre, Gerardo; Parra‐Hake, Miguel; Somanathan, Ratnasamy

doi:10.1016/j.tetasy.2013.08.014

Cited by 26 publications

(18 citation statements)

References 44 publications

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“…Asymmetric transfer hydrogenation (ATH) of ketones by organometallic homogeneous catalysis in water is of abundant attention in green chemistry. Recently, many have described the ATH of ketones in water solvent under non‐inert conditions, which are useful for industrial applications . Chiral Ru (II)‐ p ‐cymene complexes are found to be promising catalysts for ATH of ketones.…”

Section: Introductionmentioning

confidence: 99%

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

Sheeba

Tamizh

Bhuvanesh

et al. 2018

Applied Organom Chemis

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The newfangled chiral aroylthiourea ligands (L1‐L6) were produced from unprotected D/L‐alanine and their water soluble Ru (II) organometallic catalysts (1–6) were designed from their reaction with [RuCl2(η6‐p‐cymene)]2. The analytical and spectral methods were used to confirm the structure of the ligands and complexes. The solid state structure of L1, 5 and 6 was confirmed by single crystal XRD. The organometallic compounds (1–6) catalyzed the asymmetric transfer hydrogenation of aromatic, heteroaromatic and bulky ketones to yield respective enantiopure secondary alcohols with admirable conversions (up to 99%) and attractive enantiomeric excesses (ee up to 98%), in presence of formic acid and triethylamine in water medium under non‐inert atmospheric conditions.

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Section: Introductionmentioning

confidence: 99%

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

Sheeba

Tamizh

Bhuvanesh

et al. 2018

Applied Organom Chemis

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“…[13][14][15] It was also found that arene ruthenium complexes are much more active than classical Ru(II) catalysts. The chiral ligands used with [RuCl 2 (η 6 -C 6 H 6 )] 2 are diamines, 33 Ntosylethylenediamine, 34 monophosphorus ligands, 35 N-heterocyclic carbenes, 36 amino carboxylate, 37 aromatic monosulfonamide, 38 ether-based linking ligands, 39 (1R,2R)-N- 3 (naphthalene-1-sulfonyl)-1,2-diphenylethylenediamine, 40 ferrocene based phosphinite, 41 2,2'dipyridylamine, di-2-pyridylbenzylamine, 42 β-cyclodextrin, 43 (2R,5R)-2,5-diphenylpyrrolidine, 44 amino alcohols, 45 bis(pyrazolyl)methane, 46 chiral amines 47 , etc. [30][31] Ru(II) complexes synthesized from [RuCl 2 (η 6 -arene)] 2 and monotosylated 1,2-diamine ligands act as efficient catalysts for the ATH of ketones via a metal ligand bifunctional mechanism.…”

Section: Introductionmentioning

confidence: 99%

Half-sandwich Ru(η⁶-C₆H₆) complexes with chiral aroylthioureas for enhanced asymmetric transfer hydrogenation of ketones – experimental and theoretical studies

Sheeba

Preethi

Nijamudheen

et al. 2015

Catal. Sci. Technol.

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The reactions of [RuCl 2 (η 6 -C 6 H 6 )] 2 with chiral aroylthiourea ligands yielded pseudo octahedral half-sandwich "piano-stool" complexes. All the Ru(II) complexes were characterized by analytical and spectral (UV-visible, FT-IR, 1 H NMR and 13 C NMR) studies. The molecular structure of the ligands (L2 and L4) and the complexes (2, 4 and 5) was confirmed by single crystal XRD. All the complexes were successfully screened as catalysts for the asymmetric transfer hydrogenation (ATH) of ketones using 2-propanol as the hydrogen source in the presence KOH. The ATH reactions proceeded with excellent yields (up to 99%) and very good enantioselectivity (up to 99% ee). The scope of the present catalytic system was extended to substituted aromatic ketones and few hetero aromatic ketones. Density functional theory (DFT) calculations predicted non-classical, concerted transition states for the ATH reactions. The catalytic activity of Ru-benzene complexes toward asymmetric reduction of ketones was significantly higher compared to analogues p-cymene complexes. Such enhanced efficiency and the product selectivity for Ru-benzene complexes compared to Ru-p-cymene complexes were rationalized by the computational study.Electronic supplementary information (ESI) available: A table of the X-ray crystallographic data, atomic coordinates in CIF format, the molecular structure of ligands L2 & L4, 1 H NMR and 13 C NMR spectra of all the ligands and complexes, GC and HPLC data are included. Cartesian coordinates, energies, and vibrational frequencies for all the reported structures, and optimized geometries and activation free energies for high energy TSs.

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“…[8a-8d] Furthermore, complexes containing sulfonamide groups have been used to catalyze various organic reactions, for example, olefin metathesis, asymmetric transfer hydrogenation (TH), the nitroaldol (Henry) reaction, and so on. [9][10][11] Sulfonamides containing 8-aminoquinoline have rarely been studied by the scientific community, and mostly only in relation to their luminescent properties. [12][13][14][15][16] Also, catalysis and the molecular structural properties of sulfonamides have recently been studied in detail by our research team.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Half‐Sandwich Ruthenium Complexes Containing Aromatic Sulfonamides Bearing Pyridinyl Rings: Catalysts for Transfer Hydrogenation of Acetophenone Derivatives

et al. 2013

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Keywords: Transfer hydrogenation / Sulfonamides / Ruthenium / N ligands benzenesulfonamides 1-6 were successfully synthesized by the reaction of 8-aminoquinoline and various benzenesulfonyl chlorides. Then, half-sandwich ruthenium complexes 7-12 were prepared from the reactions of 1-6 with [RuCl 2 (p-cymene)] 2 . The synthesized compounds were characterized by NMR and FTIR spectroscopy and elemental analysis, and compounds 8 and 9 were further ana- [a]3224 lyzed by X-ray diffraction. The complexes were screened for their efficiency as catalysts in the transfer hydrogenation of acetophenone derivatives to phenylethanols in the presence of KOH with 2-propanol (as hydrogen source) at 82°C, and they all showed good activity. Complexes 10 and 12 were the most active (turnover frequency values: 703 and 734 h -1 , respectively). same time, half-sandwich ruthenium(II) complexes containing thioamides, 2-(diphenylphosphanyl)aniline, ferrocenyl tosylamine-phosphane and pyridine-based chelating diamine ligands were also studied for the catalytic TH of ketones. [34][35][36][37] Also, remarkable studies have been carried out in the TH of acetophenone derivatives. [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] Herein, a series of half-sandwich Ru II complexes containing sulfonamide ligands were synthesized and characterized by various spectroscopic techniques. The synthesized complexes were used as catalysts for the TH of acetophenone derivatives. Results and Discussion SynthesesThe synthesis and reaction routes to the ligands and to their corresponding Ru II complexes are presented in Fig-Figure 1. Synthesis of the ligands together with their NMR numbering scheme. Eur. J. Inorg. Chem. 2013, 3224-3232 Eur. J. Inorg. Chem. 2013, 3224-3232 {[N-Quinoline-8-yl-4-(trifluoromethyl)benzenesulfonamido](p-cymene)chlororuthenium(II)} (12): Yield 83 %, dark red microcrystals, m.p. 245-247°C. 1 H NMR (CDCl 3 ): δ = 0.94 and 1.09 (d and d,

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Synthesis of (R)-tembamide and (R)-aegeline via asymmetric transfer hydrogenation in water

Cited by 26 publications

References 44 publications

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

Half-sandwich Ru(η⁶-C₆H₆) complexes with chiral aroylthioureas for enhanced asymmetric transfer hydrogenation of ketones – experimental and theoretical studies

Synthesis and Characterization of Half‐Sandwich Ruthenium Complexes Containing Aromatic Sulfonamides Bearing Pyridinyl Rings: Catalysts for Transfer Hydrogenation of Acetophenone Derivatives

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Synthesis of (R)-tembamide and (R)-aegeline via asymmetric transfer hydrogenation in water

Cited by 26 publications

References 44 publications

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

Half-sandwich Ru(η6-C6H6) complexes with chiral aroylthioureas for enhanced asymmetric transfer hydrogenation of ketones – experimental and theoretical studies

Synthesis and Characterization of Half‐Sandwich Ruthenium Complexes Containing Aromatic Sulfonamides Bearing Pyr­id­inyl Rings: Catalysts for Transfer Hydrogenation of Acetophenone Derivatives

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Half-sandwich Ru(η⁶-C₆H₆) complexes with chiral aroylthioureas for enhanced asymmetric transfer hydrogenation of ketones – experimental and theoretical studies

Synthesis and Characterization of Half‐Sandwich Ruthenium Complexes Containing Aromatic Sulfonamides Bearing Pyridinyl Rings: Catalysts for Transfer Hydrogenation of Acetophenone Derivatives