Search

An asymmetric transfer hydrogenation of 2‐oxazolones in the presence of a chiral diamine ruthenium catalyst with potassium formate as a hydrogen source and potassium carbonate as an additive in 2,2,2‐trifluoroethanol is described. A series of chiral 2‐oxazolidinones were obtained with 29%–95% yields and 86%–>99% ee's. Furthermore, gram‐scale synthesis of chiral 2‐oxazolidinone and its downstream derivatizations demonstrate the practicality of this method. [ABSTRACT FROM AUTHOR]

A one‐pot synthesis of fluorinated chiral alcohols from α‐bromoarylketones and fluoroalcohols is described. The fluorinated ketone intermediates were formed from α‐bromoarylketones with fluoroalcohols as nucleophiles and solvents, which were reduced subsequentially by adding a chiral Ru catalyst and a mixture of formic acid and triethyl amines (FA: TEA=1.1:1) as hydrogen donor to give 27 examples of fluorinated chiral alcohols in 60–93% yields and 85–98% ee values. Notably, K3PO4 acts as a base in nucleophilic substitution and an additive in reductive step to enhance the reactivity and enantioselectivity, which is crucial for constructing compatible conditions for one‐pot process. This one‐pot process is also applicable to gram‐scale synthesis. [ABSTRACT FROM AUTHOR]

An exclusive asymmetric reduction of C＝O bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols in up to 96% yield and 99% ee. This method was also applicable to the gram-scale synthesis of the active intermediates of the anti-inflammatory loxoprofen and natural product (−)-goniomitine. [ABSTRACT FROM AUTHOR]

An asymmetric transfer hydrogenation of 2‐oxo alkyl phosphinates in the presence of a chiral diamine ruthenium catalyst with HCOONa as a hydrogen source in aqueous 2,2,2‐trifluoroethanol under mild conditions gave a wide range of chiral 2‐hydroxyalkyl diarylphosphinates in enantiomeric excesses of 97–99% and in good yields. The absolute configuration of the products was determined to be R by single‐crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

A highly efficient transfer hydrogenation of quinolines with Hantzsch ester as hydrogen source in the presence of 1 mol% Fe(OTf) 2 under mild conditions has been developed. A series of substituted 1,2,3,4-tetrahydroquinoline derivatives were afforded in excellent yields with good functional group tolerance. [ABSTRACT FROM AUTHOR]

[Display omitted] • An operationally simple and green method for chemoselective reduction of 2-benzylidene indanones and analogues to saturated ketones with water as a sole solvent is described. • Water soluble iridium pyridine-imidazoline complex was used as a catalyst with a mixture of formic acid/triethyl amine as a hydrogen source. • This method has a good functional group tolerance and is also applicable to gram-scale synthesis. A chemoselective iridium-catalyzed transfer hydrogenation of α, β-unsaturated ketones was realized in water. The C C double bonds of 2-benzylidene indanones and analogues were hydrogenated exclusively catalyzed by an iridium complex (0.1 mol%) bearing a pyridine-imidazoline ligand, using a mixture of formic acid/triethyl amine (molar ratio: 5/2) as a hydrogen source in water. A series of 2-benzyl indanones and analogues were obtained with good functional group tolerance and good yields. The practicability of this approach is also demonstrated by a gram-scale synthesis. [ABSTRACT FROM AUTHOR]

• Compatible redox with simple catalytic system. • One-pot deracemization transformation. • Wide substrate scope and good enantioselectivity. The deracemization of benzylic alcohols has been achieved using a redox-driven one-pot two-step process. The racemic alcohols were oxidized by bis(methoxypropyl) ether and oxygen to give the ketone intermediates, followed by an asymmetric transfer hydrogenation with a chiral ruthenium catalyst. This compatible oxidation/reduction process gave the enantiomerically enriched alcohols with up to 95% ee values. [ABSTRACT FROM AUTHOR]