16183-45-2Relevant articles and documents
Chemoselective N-heterocyclic carbene-catalyzed cross-benzoin reactions: Importance of the fused ring in triazolium salts
Langdon, Steven M.,Wilde, Myron M.D.,Thai, Karen,Gravel, Michel
supporting information, p. 7539 - 7542 (2014/06/10)
Morpholinone- and piperidinone-derived triazolium salts are shown to catalyze highly chemoselective cross-benzoin reactions between aliphatic and aromatic aldehydes. The reaction scope includes ortho-, meta-, and para-substituted benzaldehyde derivatives with a range of electron-donating and -withdrawing groups as well as branched and unbranched aliphatic aldehydes. Catalytic loadings as low as 5 mol % give excellent yields in these reactions (up to 99%).
Chemoselective and repetitive intermolecular cross-acyloin condensation reactions between a variety of aromatic and aliphatic aldehydes using a robust N-heterocyclic carbene catalyst
Jin, Ming Yu,Kim, Sun Min,Mao, Hui,Ryu, Do Hyun,Song, Choong Eui,Yang, Jung Woon
supporting information, p. 1547 - 1550 (2014/03/21)
We found that chemoselectivity of the crossed acyloin product is controlled by the adjustment of the aromatic aldehyde/aliphatic aldehyde ratio. Moreover, we observed the persistent catalytic activity of the homogeneous NHC catalyst in a solution due to N
Stereoselective synthesis of norephedrine and norpseudoephedrine by using asymmetric transfer hydrogenation accompanied by dynamic kinetic resolution
Lee, Hyeon-Kyu,Kang, Soyeong,Choi, Eun Bok
experimental part, p. 5454 - 5460 (2012/08/27)
Each of the enantiomers of both norephedrine and norpseudoephedrine were stereoselectively prepared from the common, prochiral cyclic sulfamidate imine of racemic 1-hydroxy-1-phenyl-propan-2-one by employing asymmetric transfer hydrogenation (ATH) catalyzed by the well-defined chiral Rh-complexes, (S,S)- or (R,R)-Cp*RhCl(TsDPEN), and HCO2H/Et3N as the hydrogen source. The ATH processes are carried out under mild conditions (rt, 15 min) and are accompanied by dynamic kinetic resolution.
Enantioselective aerobic oxidation of α-hydroxy-ketones catalyzed by oxidovanadium(V) methoxides bearing chiral, N-salicylidene- tert -butylglycinates
Chen, Chien-Tien,Kao, Jun-Qi,Salunke, Santosh B.,Lin, Ya-Hui
, p. 26 - 29 (2011/03/22)
Chiral oxidovanadium(V) methoxides prepared from 3,5-disubstituted-N- salicylidene-l-tert-butylglycines and vanadyl sulfate in air-saturated MeOH serve as highly enantioselective catalysts for asymmetric aerobic oxidations and kinetic resolution of alkyl, aryl, and heteroaryl α-hydroxy-ketones with differed α-substituents at ambient temperature in toluene or TBME (tert-butyl methyl ether). The best scenarios involve the use of complexes which bear the tridendate templates derived from 3,5-diphenyl- or 3-o-biphenyl-5-nitro-salicyaldehyde. The kinetic resolution selectivities of the aerobic oxidation process are in the range of 12 to >1000 based on the selectivity factors (krel).
One-pot synthesis of α-hydroxy ketones from captodative formyl(amino)alkenes
Rulev, Alexander Yu.,Novokshonov, Vladimir V.,Chuvashev, Yuri A.,Fedorov, Sergei V.,Larina, Lyudmila I.
, p. 23 - 25 (2007/10/03)
α-Hydroxy or α-amino ketones were prepared in one step via reactions between captodative formyl(amino)alkenes and Grignard reagents.
Stereoselective Synthesis of Optically Active α-hydroxy Ketones and anti-1,2-diols via Asymmetric Transfer Hydrogenation of Unsymmetrically Substituted 1,2-diketones
Koike, Takashi,Murata, Kunihiko,Ikariya, Takao
, p. 3833 - 3836 (2007/10/03)
Formula Represented A well-defined chiral Ru catalyst RuCl(N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine)(η6-arene) effectively promotes asymmetric transfer hydrogenation of 1-aryl-1,2-propanedione with HCOOH/N(C2H5)3, leading preferentially to optically active 1-aryl-2-hydroxy-1-propanone with up to 99% ee and 89% yield at 10°C. The reaction at 40°C gives anti-1-aryl-1,2-propanediol with up to 95% ee and 78% yield. This is a highly efficient procedure for the synthesis of optically active anti-diols.
Asymmetric reduction of α-keto esters and α-diketones with a bakers' yeast keto ester reductase
Kawai, Yasushi,Hida, Kouichi,Tsujimoto, Munekazu,Kondo, Shin-Ichi,Kitano, Kazutada,Nakamura, Kaoru,Ohno, Atsuyoshi
, p. 99 - 102 (2007/10/03)
Optically pure α-hydroxy esters and α-hydroxy ketones have been synthesized by the reduction of the corresponding ketones with a keto ester reductase isolated from bakers' yeast (YKER-I). The reduction of α-keto esters affords the corresponding (S)- or (R)-hydroxy esters selectively, where the stereochemical course depends on the chain length of the alkyl substituent on the carbonyl group. An α-keto short alkanoic ester affords the corresponding (S)-hydroxy ester, whereas a long alkanoate yields the corresponding (R)-hydroxy ester. The reduction of α-diketones affords the corresponding (S)-2-hydroxy ketones regio- and stereoselectively.
AZO ANIONS IN SYNTHESIS. PT 1. t-BUTYLHYDRAZONES AS ACYL-ANION EQUIVALENTS
Baldwin, Jack E.,Adlington, Robert M.,Bottaro, Jeffrey C.,Kolhe, Jayant N.,Perry, Matthew W. D.,Jain, Ashok U.
, p. 4223 - 4234 (2007/10/02)
The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides, crotonates) to form C-trapped t-butylazo-compounds; tautomerisation and hydrolysis gave α-hydroxy ketones, ketones, and γ-keto esters in good yield, thereby providing a convenient new acyl-anion equivalent.Reaction of these lithium salts with aldehydes and ketones, followed by elimination provided a new route to azo alkenes.
Tandem Alkylation-Reduction. Highly Stereoselective Synthesis of (E)-1-Hydroxymethyl Methyl Propenyl Ethers from Aldehydes Using 1-Lithio-1-methoxyallene
Weiberth, Franz J.,Hall, Stan S.
, p. 5308 - 5314 (2007/10/02)
Tandem alkylation-reduction of a series of aldehydes, by alkylating with 1-lithio-1-methoxyallene followed by reducing with lithium-ammonia, regiospecifically and highly stereoselectively affords the 1-hydroxymethyl methyl propenyl ether in which the alkene geometry is exclusively E.Aldehydes that have been subjected to this convenient procedure include aromatic, aliphatic, and heterocyclic aldehydes.Subsequent hydrolysis, in the aromatic and aliphatic cases, affords the corresponding α-hydroxy ethyl ketones.The stereochemistry of the propenyl ethers was established by 13C NMR spectroscopy.A mechanism for the selective reduction of the methoxyallene system is proposed.
Azo Anions in Synthesis. t-Butylhydrazones as Acyl-anion Equivalents
Adlington, Robert M.,Baldwin, Jack E.,Bottaro, Jeffrey C.,Perry, Matthew W. D.
, p. 1040 - 1041 (2007/10/02)
The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides) to form C-trapped t-butylazo compounds; isomerisation and hydrolyse gave α-hydroxy ketones and ketones in good yields, thereby providing a convenient new acyl-anion equivalent.