117465-37-9

Upstream product

• 117340-79-1 2-bromo-1-(4-methoxyphenyl)ethanol 
• 2632-13-5 2-Bromo-4'-methoxyacetophenone 
• 876-27-7 4-chlorophenyl acetate 
• 33675-41-1 1-bromo-2-(4-methoxyphenyl)acetylene 
• 22651-87-2 cyclohexanecarboxylic acid anhydride 

Downstream Products

• 341513-45-9 (R)-β-azido-α-(4-methoxyphenyl)ethanol 
• 62600-73-1 (R)?4?methoxyphenyloxirane 

Relevant academic research and scientific papers

Integration of multiple active sites on large-pore mesoporous silica for enantioselective tandem reactions

Facile construction of a multifunctional heterogeneous catalyst through the assembly of Au/carbene and chiral ruthenium/diamine dual complexes in large-pore mesoporous silica was developed. This enables an efficient one-pot hydration-asymmetric transfer hydrogenation enantioselective tandem reaction of haloalkynes, affording chiral halohydrins with up to 99% enantioselectivity. Combined multifunctionalities, such as substrate-promoted silanol-functionality, BF4? anion-bonding gold/carbene and covalent-bonding chiral ruthenium/diamine active centers, contributed cooperatively to the catalytic performance.

Enantioselective reduction of ketones with triethoxysilane catalyzed by chiral bis-oxazoline titanium complexes

Chiral bis-oxazoline titanium complexes [Ti(BOX)2X2] prepared from C2 chiral bis-oxazolines, BuLi and titanium salts, catalyze the enantiosective reduction of ketones in the presence of triethoxysilane.

Bis(oxazoline)titanium complexes as chiral catalysts for enantioselective hydrosilylation of ketones - A combined experimental and theoretical investigation

A combined experimental and theoretical investigation has been carried out on a new catalytic system, based on bis-(oxazoline) (BOX) complexes of titanium. These catalytic species are able to reduce aromatic ketones with good enantiomeric excesses and satisfactory yields. The experimental and the computational (DFT) evidence has provided useful information on the nature of the active catalytic species and on the mechanism of the reaction. The most likely reaction path involves a TiIV catalytic species. This result agrees with experimentally obtained evidence that seems to rule out the presence of TiIII species. The analysis of the structure of the transition state corresponding to the reduction process (the addition of the hydride to the carbonyl system), provides an interesting insight on the enantioselectivity that characterizes this reaction. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Chiral guanidine catalyzed acylative kinetic resolution of racemic 2-bromo-1-arylethanols

In this study, chiral guanidine catalyzed acylative kinetic resolution of racemic 2-bromo-1-arylethanols was achieved with high selectivity. Irrespective of the electronic nature and the substitution patterns on the aromatic rings, a variety of substrates were suitable for this reaction. The branched acyl component was considered to be optimal for obtaining high s-values. The transition state of the reaction was proposed based on the absolute configuration of the obtained product.

Asymmetric Catalytic Meerwein-Ponndorf-Verley Reduction of Ketones with Aluminum(III)-VANOL Catalysts

We report herein an efficient aluminum-catalyzed asymmetric MPV reduction of ketones with broad substrate scope and excellent yields and enantiomeric inductions. A variety of aromatic (both electron-poor and electron-rich) and aliphatic ketones were converted to chiral alcohols in good yields with high enantioselectivities (26 examples, 70-98percent yield and 82-99percent ee). This method operates under mild conditions (-10 °C) and low catalyst loading (1-5 mol percent). Furthermore, this process is catalyzed by the earth-abundant main-group element aluminum and employs 2-propanol as the hydride source.

Asymmetric synthesis of α-bromohydrins by carrot root as biocatalyst and conversion to enantiopure β-hydroxytriazoles and styrene oxides using click chemistry and SN2 ring-closure

In this study we have combined the bioreduction of α-bromoketones using carrot root as biocatalyst and click chemistry for the preparation of enantiopure β-hydroxytriazoles in excellent enantiomeric excesses and yields. Moreover, we have utilized chiral α-halohydrins for the synthesis of enantiopure styrene oxides in very good yields and enantiomeric excesses. Structural assignments of the products were based on their 1H and 13C NMR data and their optical rotations. The enantiomeric excess of the chiral products was obtained by HPLC analysis.

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

A practical method for the asymmetric transfer hydrogenation of α-substituted ketones was developed utilizing oxo-tethered N-sulfonyldiamine-ruthenium complexes. Reduction by HCO2H and HCO2K in a mixed solvent of EtOAc/H2O 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 HCO2H and Et3N. 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 α-sulfonated ketones without eroding the leaving group. (Figure presented.).

One-Pot cascade hydration-asymmetric transfer hydrogenation as a practical strategy to construct chiral β-adrenergic receptor blockers

The facile construction of biologically active β-adrenergic receptor agonists/blockers and analogues is a great fundamental and practical challenge in medical chemistry. Herein, we report a hydration-asymmetric transfer hydrogenation cascade to realize the one-pot enantioselective transformation of aromatic haloalkynes into chiral aromatic halohydrins, which can be converted readily into chiral β-adrenergicreceptor blockers. Such a one-pot cascade process involves the Au-catalyzed hydration of aryl-substituted haloalkynes to aryl-substituted α-halomethyl ketones and the Ru-catalyzed asymmetric transfer hydrogenation of aryl-substituted α-halomethyl ketones to aryl-substituted 2-haloethanols. The significant benefits of this procedure are that it provides chiral aromatic halohydrins in high yields, with excellent enantioselectivities, and a wide variety of functional groups are tolerated under mild conditions. The study described herein offers a useful approach to construct chiral β-adrenergic blockers, which is an attractive practical organic transformation that is performed in a one-pot manner.

Surfactant-accelerated asymmetric transfer hydrogenation with recyclable water-soluble catalyst in aqueous media

Water-soluble ligands (R,R)-2 were successfully prepared, in which the bis-meta-sulphonated ligand was definitely detected as the major product. The corresponding transition-metal complexes containing the ligands displayed excellent catalytic performance in asymmetric transfer hydrogenation (ATH) of aromatic ketones. Especially, the aromatic ketones with a bromine group in the α position could be smoothly reduced to the expected alcohol, keeping the bromine group intact with excellent enantioselectivities (up to 96% ee). The catalyst could be reused at least 21 times without erosion of the enantioselectivity in high conversion. Moreover, it was found that cationic surfactant and proper pH values were necessary for the maintenance of high reactivity.

Copper(II)-catalyzed hydrosilylation of ketones using chiral dipyridylphosphane ligands: Highly enantioselective synthesis of valuable alcohols

In the presence of PhSiH3 as the reductant, the combination of enantiomeric dipyridylphosphane ligands and Cu(OAc)2·H 2O, which is an easy-to-handle and inexpensive copper salt, led to a remarkably practical and versatile chiral catalyst system. The stereoselective formation of a selection of synthetically interesting β-, γ- or δ-halo alcohols bearing high degrees of enantiopurity (up to 99.9 % enantiomeric excess (ee)) was realized with a substrate-to-ligand molar ratio (S/L) of up to 10 000. The present protocol also allowed the hydrosilylation of a diverse spectrum of alkyl aryl ketones with excellent enantioselectivities (up to 98 % ee) and exceedingly high turn-over rates (up to 50 000 S/L molar ratio in 50 min reaction time) in air, under very mild conditions, which offers great opportunities for the preparation of various physiologically active targets. The synthetic utility of the chiral products obtained was highlighted by the efficient conversion of optically enriched β-halo alcohols into the corresponding styrene oxide, β-amino alcohol, and β-azido alcohol, respectively.