- Chiral ferrocene P-N-N ligand with high steric hindrance, and preparation method and application thereof
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The invention provides a chiral ferrocene P-N-N ligand compound with high steric hindrance, and a preparation method and application thereof, specifically application of the chiral ferrocene P-N-N ligand compound to asymmetric catalytic hydrogenation of beta-keto ester compounds. The preparation method for the chiral ferrocene P-N-N ligand compound with high steric hindrance comprises the following steps: dissolving a chiral ferrocenephosphine-amine compound and a pyridone compound in a reaction solvent; adding active Al2O3 and a dehydrating agent; carrying out a reflux condensation reaction; then carrying out re-dissolving in absolute ethyl alcohol after filtering and desolventizing; adding a palladium/carbon catalyst and carrying out a hydrogenation reaction in an autoclave under a certain reaction pressure; and then successively carrying out filtration, desolventizing and column chromatographic treatment so as to obtain the desired chiral ferrocene P-N-N ligand compound with high steric hindrance. The chiral ferrocene P-N-N ligand compound with high steric hindrance in the invention can be used for asymmetric catalytic hydrogenation of beta-keto ester and can realize high-yield, high-diastereoselectivity high-enantioselectivity preparation of chiral beta-hydroxy ester.
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Paragraph 0125-0129
(2018/01/13)
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- Reductive aldol-type reaction of α,β-unsaturated esters with aldehydes or ketones in the presence of Rh catalyst and Et2Zn
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The reaction of RhCl(PPh3)3 with Et2Zn easily generated a rhodium-hydride complex (Rh-H) that added to α,β-unsaturated esters to form rhodium enolate complexes by formal 1,4-reduction. These rhodium enolates gave the corre
- Sato, Kazuyuki,Isoda, Motoyuki,Tokura, Yoriko,Omura, Keiko,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
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p. 5913 - 5915
(2013/10/21)
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- Copper-ClickFerrophos-complex-catalyzed enantioselective reductive aldol reaction
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We have prepared several ClickFerrophos families and tested for the Cu(I)-catalyzed asymmetric reductive aldol reaction of ketones and aldehydes with an acrylic ester in the presence of phenylsilane. The Cu(I)-ClickFerrophos complex is efficient for the r
- Kato, Minoru,Oki, Hiroshi,Ogata, Kenichi,Fukuzawa, Shin-Ichi
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experimental part
p. 1299 - 1302
(2009/12/03)
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- Copper(I)-catalyzed enantio- and diastereoselective tandem reductive aldol reaction
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(Chemical Equation Presented) An efficient method for the enantioselective tandem reductive aldol reaction of methyl acrylate with aldehydes is reported. By using a copper-(I) precursor and a proper diphosphane ligand, high reactivities can be reached, with TOF up to 40 000 h-1. Taniaphos-based ligands lead to enantioselectivities of up to 97% in the case of the major syn diastereoisomer.
- Chuzel, Olivier,Deschamp, Julia,Chausteur, Christophe,Riant, Olivier
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p. 5943 - 5946
(2007/10/03)
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- Catalytic generation of activated carboxylates: Direct, stereoselective synthesis β-hydroxyesters from epoxyaldehydes
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The catalytic generation of activated carboxylates from epoxyaldehydes enables the direct, stereoselective synthesis of β-hydroxyesters under mild, convenient reaction conditions. In addition to providing a new method for the synthesis of anti-aldol adducts, this chemistry unveils a mechanistically viable solution to the catalytic, waste-free synthesis of esters. Copyright
- Chow, Kenneth Yu-Kin,Bode, Jeffrey W.
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p. 8126 - 8127
(2007/10/03)
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- Chemistry of enoxysilacyclobutanes: Highly selective uncatalyzed aldol additions
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O-(Silacyclobutyl) ketene acetals derived from esters, thiol esters, and amides underwent facile aldol addition with a variety of aldehydes at room temperature without the need for catalysts. The uncatalyzed aldol addition reaction of O-(silacyclobutyl) ketene acetals displayed the following characteristics: (1) the rate of reaction was highly dependent on the spectator substituent on silicon and the geometry of the ketene acetal, (2) the O,O-ketene acetal of E configuration afforded the syn aldol products with high diastereoselectivity (93/7 to 99/1), (3) conjugated aldehydes reacted more rapidly than aliphatic aldehydes, and (4) the reaction was mildly sensitive to solvent. In addition, the aldol reaction was found to be efficiently catalyzed by metal alkoxides. Labeling experiments revealed that the thermal aldol reaction proceeds by direct intramolecular silicon group transfer, while the alkoxide-catalyzed version probably proceeds via in situ generated metal enolates. Computational modeling of the transition states suggests that the boat transition structures are preferred, supporting the observed syn selectivity of the thermal aldol reaction. Both thermal and alkoxide-catalyzed Michael additions were investigated, revealing a competition between 1,2- and 1,4-addition favoring the former.
- Denmark, Scott E.,Griedel, Brian D.,Coe, Diane M.,Schnute, Mark E.
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p. 7026 - 7043
(2007/10/02)
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- Stereoselective Acetalization of 1,3-Alkanediols by l-Menthone: Application to the Resolution of Racemic 1,3-Alkanediols and to the Determination of the Absolute Configuration of Enantiomeric 1,3-Alkanediols
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A general and reliable method for the resolution of racemic 1,3-alkanediols, which involves their conversion into diastereomeric spiroacetals derived from l-menthone, is described.Thus, the reaction of the bis-O-trimethylsilyl derivatives of racemic 1,3-alkanediols with l-menthone in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate affords the diastereomeric spiroacetals 3 and 4.The two can be readily separated by silica gel column chromatography.Hydrolysis of each diastereomer under acidic conditions liberates the corresponding enantiomerically pure diol.An empirically derived correlation of configuration and 1H NMR chemical shifts for spiroacetals 3 and 4 has been developed which is rationalized based on long-range effects due to the magnetic anisotropy inherent to the menthane ring in a rigid spiroacetal conformation.The method described here should be widely applicable to the determination of the absolute configuration of various 1,3-alkanediols.
- Harada, Toshiro,Kurokawa, Hideaki,Kagamihara, Yasuhiro,Tanaka, Sachi,Inoue, Atsushi,Oku, Akira
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p. 1412 - 1421
(2007/10/02)
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- Synthesis of Optically Active (E)-1-Alkoxymethoxybut-2-enyl(tributyl)stannanes: Stereochemistry of their Thermal Reactions with Aldehydes
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(1R)- and (1S)-1--(E)-but-2-enyl(tributyl)stannanes (8) and (9), whose configurations were assigned by correlation with (2R)- and (2S)-pentan-2-ol (14) and (15), react stereoselectively on heating with benzaldehyde to give (3S,4S)- and (3R,4R)-4-hydroxy-3-methyl-(Z)-1,2-enol ethers (16) and (18), respectively, the configurations of these products being established by correlation with pseudoephedrine.
- Jephcote, Vincent J.,Pratt, Andrew J.,Thomas, Eric J.
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p. 1529 - 1535
(2007/10/02)
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- Chemistry of Ketene Acetals. Part 8. Stereochemistry of the Reaction of 1,1-Dimethoxypropene with Aldehydes
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The Lewis acid-catalysed (2+2)cycloadditions of 1,1-dimethoxypropene with various aldehydes RCHO have been studied.These reactions, which are supposed to proceed via dipolar intermediates, yield 2,2-dimethoxyoxetanes, the formation of which is reversible
- Hofstraat, Rob G.,Scheeren, Hans W.,Nivard, Rutger J. F.
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p. 561 - 564
(2007/10/02)
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- STEREOSELECTIVITY IN THE ALDOL REACTION THE USE OF CHIRAL AND ACHIRAL OXAZOLINES AS THEIR BORON AZENOLATES
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Chiral oxazolines, as their boron enolates derived from various boron triflates, react with aldehydes to give erythro-selectivity (97percent+percent) with enantiomeric purities of 50-60percent.Achiral oxazolines as their boron enolates derived from diisopinocamphenylborane give, on reaction with aldehydes, β-hydroxy esters with high threo-selectivity (90+percent) in 77-85percent ee.A variety of stucturally different oxazolines were also studied and many show high erythro-selectivity.
- Meyers, A. I.,Yamamoto, Yukio
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p. 2309 - 2315
(2007/10/02)
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- Synthesis and Absolute Configuration of Optically Active E-1-Alkoxymethoxybut-2-enyl(tri-n-butyl)stannanes: Stereoselective Reactions with Aldehydes
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(1R)- and (1S)-1--E-but-2-enyl(tri-n-butyl)stannanes (5) and (6), whose configurations at C(1) were assigned by correlation with (2R)- and (2S)-pentan-2-ol, react stereoselectively on heating with benzaldehyde to give (3S,4S)- and (3R,4R)-4-hydroxy-3-methyl-cis-1,2-enol ethers (11) and (13), respectively.
- Jephcote, Vincent J.,Pratt, Andrew J.,Thomas, Eric J.
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p. 800 - 802
(2007/10/02)
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