27544-18-9Relevant academic research and scientific papers
Asymmetric reduction of ketones with sodium aluminum hydride modified by various chiral diols
Vinogradov,Gorshkova,Pavlov,Mikhalev,Chel'tsova,Razmanov,Ferapontov,Malyshev,Heise
, p. 460 - 465 (2000)
New stereoselective reducing reagents were prepared in situ by modification of NaAlH4 with various chiral diols. The efficiency of 1,4- and 1,3-diols as chiral auxiliaries in the reactions of alkyl aryl ketones with modified NaAlH4 was considerably higher than that of 1,2-diols. The effect of the nature of the achiral ligand additionally introduced into the chiral hydride reagent on the enantioselectivity of ketone reduction was studied. It was proposed that the sodium cation does not necessarily participate at the stage governing the reaction stereochemistry.
Catalytic asymmetric addition of diphenylphosphine oxide to cyclic imines
Yamakoshi, Koichi,Harwood, Simon J.,Kanai, Motomu,Shibasaki, Masakatsu
, p. 2565 - 2568 (1999)
The catalytic asymmetric addition of diphenylphosphine oxide to cyclic imines is reported for the fast time. The addition, catalyzed by a heterobimetallic lanthanoid complex, gives the corresponding amino phosphine oxide products in good to excellent yiel
Periodic mesoporous organosilicas with trans-(1R,2R)-diaminocyclohexane in the framework: A potential catalytic material for asymmetric reactions
Jiang, Dongmei,Yang, Qihua,Wang, Hong,Zhu, Guiru,Yang, Jie,Li, Can
, p. 65 - 73 (2006)
With benzyl group as a linker, trans-(1R,2R)-diaminocyclohexane was incorporated into the framework of mesoporous silica through one-step co-condensation of tetramethoxysilane with N,N′-bis[4-(trimethoxysilyl) benzyl]-(-)-(1R,2R)-diaminocyclohexane using cetyltrimethylammonium bromide as a structure-directing agent under basic conditions. All materials were fully characterized by X-ray diffraction, N2 sorption isotherms, transmission electron microscopy, and 13C and 29Si cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy. Coordinated with [Rh(cod)Cl]2, the material exhibited a TOF up to ～414 h-1 with 30% ee for the asymmetric transfer hydrogenation of acetophenone. Various ketones were hydrogenated with different activities and enantioselectivities. An enantioselectivity of about 61% ee was observed in the case of 2-acetylnaphthalene. Moreover, a comparison of the catalytic properties of the materials with benzyl and propyl groups as linkers indicates the importance of the rigidity and electron-withdrawing ability of the linker in the high reaction rate of the catalysts.
Asymmetric reduction of ketones with sodium aluminum hydride modified with chiral amino alcohols
Vinogradov,Mikhalev,Pavlov,Ferapontov,Malyshev,Heise
, p. 843 - 845 (2001)
Asymmetric reduction of ketones with hydride complexes, which were prepared by in situ modification of NaAlH4, with various chiral amino alcohols or diamines, was studied. The highest enantioselectivity (up to 93% ee) was achieved using 2-(hydroxydiphenyl-methyl)pyrrolidine as a chiral inducing agent.
The Size-Accelerated Kinetic Resolution of Secondary Alcohols
P?lloth, Benjamin,Sibi, Mukund P.,Zipse, Hendrik
, p. 774 - 778 (2021)
The factors responsible for the kinetic resolution of alcohols by chiral pyridine derivatives have been elucidated by measurements of relative rates for a set of substrates with systematically growing aromatic side chains using accurate competitive linear regression analysis. Increasing the side chain size from phenyl to pyrenyl results in a rate acceleration of more than 40 for the major enantiomer. Based on this observation a new catalyst with increased steric bulk has been designed that gives enantioselectivity values of up to s=250. Extensive conformational analysis of the relevant transition states indicates that alcohol attack to the more crowded side of the acyl-catalyst intermediate is favoured due to stabilizing CH-π-stacking interactions. Experimental and theoretical results imply that enantioselectivity enhancements result from accelerating the transformation of the major enantiomer through attractive non-covalent interactions (NCIs) rather than retarding the transformation of the minor isomer through repulsive steric forces.
Ruthenium-catalyzed stereospecific benzylic alkylation of optically active benzyl esters with malonate nucleophiles
Tsuji, Hiroaki,Suzuki, Koki,Kawatsura, Motoi
, (2021)
The transition metal-catalyzed stereospecific benzylic alkylation of optically active benzyl esters with active methylene compounds remains extremely rare. Herein, we describe the study for the ruthenium-catalyzed benzylic alkylation of chiral benzyl este
Studies on the Regio- and Enantioselectivity of the Lipase-catalyzed Transestriffication of 1'- and 2'-Naphthyl Alcohols in Organic Solvent
Ferraboschi, Patrizia,Casati, Silvana,Manzocchi, Ada,Santaniello, Enzo
, p. 1521 - 1524 (1995)
The Pseudomonas cepacia lipase preferentially acylates the 2'-regioisomers of a few 1'- and 2'-naphthyl alcohols; in the case of compounds 3a, 3c, 4a, 4c the (R)-alcohols (65- >98percent ee) and the (S)-acetates (62-98percent ee) are formed.
Resolution and synthesis of (S)-1-(2-naphthyl)ethanol with immobilized pea protein: as a new biocatalyst.
Nagaoka,Kayahara
, p. 1991 - 1992 (1999)
(S)-1-(2-Naphthyl)ethanol was yielded by immobilized pea (Pisum sativum L.) protein (IPP) from (R, S) 2-naphthyl ethanol (> 99% ee, yield; about 50%), in which the (R)-enantiomer was selectively oxidized to 2-acetonaphthone. IPP could be reused consecutively at least three times without any decrease of yield and optical purity.
Asymmetric reductions in aqueous media: Enzymatic synthesis in cyclodextrin containing buffers
Zelinski, Thomas,Liese, Andreas,Wandrey, Christian,Kula, Maria-Regina
, p. 1681 - 1687 (1999)
The enzymatic reduction of hydrophobic ketones in cyclodextrin containing media is reported yielding the corresponding alcohols (S)-1-(2- naphthyl)-ethanol, (S)-(E)-4-phenyl-3-en-2-ol and 1,2,3,4-tetrahydro-2- (1hydroxyethyl)-1-oxonaphthalene in good yiel
Optically active lithium 1,2-diphenyl-1,2-ethanediolate: An efficient chiral auxilliary in the enantioselective hydrosilylation of ketones
Pini,Iuliano,Salvadori
, p. 693 - 694 (1992)
In the asymmetric hydrosilylation of ketones employing lithium (1S,2S)-1,2-diphenyl-1,2-ethanediolate as chiral ligand of trimethoxysilane, alkylarylcarbinols were obtained with yield up to 95% and e.e. ranging from 12 to 82%.
