Asymmetric hydrogenation of various α-chloro aromatic ketones with Ru(OTf)(TsDPEN)(η6-arene) (TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine) produces the chiral chlorohydrins in up to 98% ee. This reaction can be conducted even on a 206-g scale. The an ketone phenol moiety has been utilized for synthesis (R)-norphenylephrine without protection−deprotection operations.

A novel ruthenabicyclic complex with base shows excellent catalytic activity in the asymmetric hydrogenation of ketones. The turnover frequency acetophenone reaches about 35,000 min(-1) best case, affording 1-phenylethanol >99% ee. Several aliphatic and base-labile ketones are smoothly converted to corresponding alcohols high enantioselectivity. cycle for this hydrogenation, which structure catalyst is maintained, proposed on basis deuteration experiment spectroscopic analysis data.

Asymmetric hydrogenation of a series α-hydroxy aromatic ketones in methanol catalyzed by Cp*Ir(OTf)(MsDPEN) (MsDPEN = N-(methanesulfonyl)-1,2-diphenylethylenediamine) affords the 1-aryl-1,2-ethanediols up to 99% ee. The reaction can be conducted with substrate-to-catalyst molar ratio as high 6000 under 10 atm H2. 1-Hydroxy-2-propanone is also hydrogenated enantioselectivity.

A catalytic system of RuII complex (see scheme; Ar=4-CH3C6H4; R=H, t-C4H9) and t-C4H9OK or NaBH4 activator has been used in the hydrogenation aromatic aliphatic acyl silanes to give α-hydroxysilanes with high enantioselectivity (R1=aryl, alkyl, alkenyl; R2=t-C4H9, C6H5). Optically active allylic are obtained 1,2-reduction α,β-unsaturated silanes. These chiral converted into 4-substituted 2-cyclopentenones without loss enantioselectivity. Supporting information for this article is available...

Efficient isomerization: The title reaction was catalyzed by the [RuCl2{(S)-tol-binap}{(R)-dbapen}]/KOH system in ethanol at 25 °C (see scheme). A series of E- and Z-configured aromatic aliphatic allylic alcohols, including a simple primary alkyl-substituted compound (E)-3-methyl-2-hepten-1-ol, were transformed into chiral aldehydes with least 99 % ee. dbapen = 2-dibutylamino-1-phenylethylamine, tol-binap 2,2'-bis(di-4-tolylphosphanyl)-1,1'-binaphthyl.

Abstract Palladium nanoparticles are prepared from palladium(II) acetate and 2 equivalents of potassium tert ‐butoxide in the presence 4‐octyne. The palladium nanoparticles‐tetrabutylammonium borohydride system shows excellent catalytic activity selectivity semihydrogenation alkynes to [( Z )‐]alkenes. hydrogenation 4‐octyne is conducted with catalyst at a substrate‐to‐palladium molar ratio 10,000–200,000 under 8 atm hydrogen give ( )‐4‐octene in>99% yield. Isomerization over‐reduction...

Enantioselective hydrogenation of alkynyl ketones catalyzed by Ru(OTf)(TsDPEN)(η6-p-cymene) (TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine) affords the propargylic alcohols in up to 97% ee. The moieties are left intact most cases. reaction can be conducted with a substrate-to-catalyst molar ratio as high 5000 under 10 atm H2. mode enantioselection is elucidated transition state models directed CH/π attractive interaction between substrate and catalytic species.

Abstract The ruthenabicyclic complex RuCl[( R )‐daipena][( )‐dm‐segphos] with potassium tert ‐butoxide catalyzes the hydrogenation of 2‐alkylquinoxalines and a 3‐methyl‐2 H ‐1,4‐benzoxazine in toluene under 20–100 atm hydrogen at 40 °C to afford S ‐configured cyclic amino products greater than 97% enantiomeric excess {DAIPENA=anion DAIPEN 2‐position an anisyl group, DAIPEN=1,1‐di(4‐anisyl)‐2‐isopropyl‐1,2‐ethylenediamine,...

Irradiation of 1-(hexa-4,5-dienoyl)indole derivatives in the presence an aromatic ketone by a high-pressure mercury lamp through Pyrex glass gave corresponding cyclized products stereoselectively high yields. The major part was all- cis-fused methylenecyclobutane-type compound produced [2+2] cycloaddition, accompanied small amounts alkynes via 1,5-hydrogen transfer biradical intermediate. Among range ketones, 3',4'-dimethoxyacetophenone found to sensitize substrate quite effectively.

Asymmetric hydrogenation of acetophenone in the presence Ru(II) catalysts coordinated by TolBINAP and a series chiral 1,2-diamines was studied. The sense degree enantioselectivity were highly dependent on N-substituents diamine ligands. N-substituent effect discussed detail. Among these catalysts, (S)-TolBINAP/(R)-DMAPEN-Ru(II) complex showed highest enantioselectivity. mode enantioface selection interpreted using transition state models based X-ray structure catalyst precursor. effected...

[reaction: see text] A catalyst system consisting of RuCl2[(S)-tolbinap][(R)-dmapen] and t-C4H9OK in 2-propanol effects asymmetric hydrogenation arylglyoxal dialkylacetals to give the alpha-hydroxy acetals up 98% ee. Hydrogenation racemic alpha-amidopropiophenones under dynamic kinetic resolution predominantly gives syn alcohols 99% ee >98% de, while reaction bezoin methyl ether anti excellent stereoselectivity.

Asymmetric hydrogenation of 3-quinuclidinone with RuBr2[(S,S)-xylskewphos](pica) in a base containing ethanol affords (R)-3-quinuclidinol 88−90% ee (XylSkewphos = 2,4-bis(di-3,5-xylylphosphino)pentane, PICA α-picolylamine). The optical purity the product is readily increased to >99% by recrystallization. 4.3-kg scale substrate-to-catalyst molar ratio 100 000 under 15 atm H2 at 30−45 °C completes 4 h. Use methanol or 2-propanol as solvent decreases catalyst efficiency. RuCl2(skewphos)(pica),...

Abstract Development of highly active catalysts has been an important research area in synthetic chemistry, especially from a practical point view. Herein, we focus on the homogeneous catalytic hydrogenation using well‐defined molecular and discuss recent advances field with regard to turnover number for these catalysts. DOI 10.1002/tcr.201100019

Abstract The asymmetric hydrogenation of aromatic γ‐ and δ‐keto esters into optically active hydroxy or diols under the catalysis a novel DIPSkewphos/3‐AMIQ–Ru II complex was studied. Under optimized conditions (8 atm H 2 , Ru complex/ t ‐C 4 9 OK=1:3.5, 25 °C) δ‐hydroxy (including γ‐lactones) were obtained quantitatively with 97–99 % ee . When reaction conducted somewhat harsh (20 [ OK]=50 m 40 °C), 1,4‐ 1,5‐diols predominantly 95–99 reactivity ester group notably dependent on length carbon...

Abstract Catalytic asymmetric hydrogenation of ketones through the “metal–ligand cooperative mechanism” has been improved in terms efficiency, stereoselectivity, and scope substrates by varying arrangement catalyst structure reaction conditions. Imino compounds are also smoothly converted to optically active amines with appropriate catalysts. This type exhibits excellent performance on isomerization primary allylic alcohols into aldehydes. personal account describes recent progress these...

Hydrogenation of 3-quinuclidinone and bicyclo[2.2.2]octan-2-one with a combined catalyst system RuCl2[(S)-binap][(R)-iphan] t-C4H9OK in 2-propanol afforded the chiral alcohols 97−98% ee. 2-Diphenylmethyl-3-quinuclidinone was hydrogenated same to cis alcohol perfect diastereo- enantioselectivity. The reaction unsymmetrical ketones bicyclo[2.2.1] or -[2.2.2] skeleton gave corresponding high stereoselectivity.

Abstract The new catalyst system of RuBr 2 [( S , )‐xyl‐skewphos][( )‐dpen] and potassium tert ‐butoxide shows high reactivity enantioselectivity in the hydrogenation N ‐arylimines [Xyl‐Skewphos=2,4‐bis(di‐3,5‐xylylphosphino)pentane, DPEN=1,2‐diphenylethylenediamine]. A range imines derived from aromatic heteroaromatic ketones as well some ferrocenyl vinylic are hydrogenated with a turnover number 18,000 under 10–50 atm hydrogen to afford amine products up 99% enantiomeric excess. reaction...

Racemic α-substituted α-amino esters were hydrogenated into enantioenriched β-amino alcohols through dynamic kinetic resolution with chiral ruthenabicyclic complexes. The reaction was carried out a substrate/catalyst molar ratio of 200-1000 under 15 atm H2 at 25 °C to afford variety β-substituted β-aminoethanols in up 96% ee (24 examples). mechanistic studies including deuteration experiments suggested that the proceeds 1,2-hydride migration acetalate intermediate α-hydroxy imine followed by...

Aza-Diels-Alder-type cycloaddition reactions between a range of N-arylimines and functionalized alkenes were effectively catalyzed by the Cr(III)/bipyridine complex under irradiation blue light, to give corresponding 1,2,3,4-tetrahydroquinoline derivatives in high yields with excellent diastereoselectivity. Typically, reaction benzylideneaniline 1-vinyl-2-pyrrolidinone proceeded smoothly substrate-to-catalyst molar ratio (S/C) 1000 completed within 4 h at room temperature (20-25 °C),...

Asymmetric hydrogenation of α-alkyl-substituted β-keto esters and amides with the DIPSkewphos/3-AMIQ–Ru(II) catalyst system through dynamic kinetic resolution was examined. A series a simple or functionalized α-alkyl group were applicable to this reaction, affording α-substituted β-hydroxy in ≥99% ee (anti/syn ≥ 99:1) many cases. The 5 g scale reaction readily achieved. mode enantio- diastereoselection transition state model proposed.

Abstract 2-Tributylstannyl-1,3-dithianes and 1-(tributylstannyl)alkyl sulfides are oxidized with ammonium hexanitratocerate(IV) or ferrocenium hexafluorophosphate to generate their cation radicals, which dissociate into the carbocations tributylstannyl radical. The thus generated react olefinic nucleophiles afford corresponding addition products in good yield.

Abstract α‐Substituted chiral ketones that have small steric and electronic differences around the reaction sites are difficult substrates to reduce with high diastereoselectivity. Metal hydride reduction of 2‐(4‐benzoylmorpholinyl) phenyl ketone 3‐(1‐ tert ‐butoxycarbonylpiperidinyl) using sodium borohydride, zinc potassium tri‐ sec ‐butylborohydride as reducing agents affords syn ‐ anti ‐alcohols in a lower than 80:20 ratio. Hydrogenation these catalyst system RuCl 2 (BIPHEP)(DMEN)...