1646862-39-6Relevant articles and documents
Chiral alpha-amido aldehyde and preparation method thereof
-
, (2020/12/29)
The invention relates to chiral alpha-amido aldehyde and a preparation method thereof. The method comprises the following steps that alpha-dehydroamido aldehyde shown in the following general formula(1) and hydrogen carry out a reduction reaction in an organic solvent under the catalytic action of a diphosphine-rhodium complex, and a chiral alpha-amido aldehyde compound shown in the following general formula (2) is obtained. The synthetic route adopts an asymmetric catalytic hydrogenation method, the process is simple, efficient and green, and the method is very suitable for industrial mass production. The product chiral amido aldehyde can be further derived into a chiral ligand and a chiral drug intermediate.
Iron-catalysed enantioconvergent Suzuki-Miyaura cross-coupling to afford enantioenriched 1,1-diarylalkanes
Tyrol, Chet C.,Yone, Nang S.,Gallin, Connor F.,Byers, Jeffery A.
supporting information, p. 14661 - 14664 (2020/12/02)
The first stereoconvergent Suzuki-Miyaura cross-coupling reaction was developed to afford enantioenriched 1,1-diarylalkanes. An iron-based complex containing a chiral cyanobis(oxazoline) ligand framework was best to obtain enantioenriched 1,1-diarylalkanes from cross-coupling reactions between unactivated aryl boronic esters and benzylic chlorides. Enhanced yields were obtained when 1,3,5-trimethoxybenzene was used as an additive, which is hypothesized to extend the lifetime of the iron-based catalyst. Exceptional enantioselectivities were obtained with challenging ortho-substituted benzylic chlorides. This journal is
Chemo- and Enantioselective Hydrogenation of α-Formyl Enamides: An Efficient Access to Chiral α-Amido Aldehydes
Zhang, Jian,Jia, Jia,Zeng, Xincheng,Wang, Yuanhao,Zhang, Zhenfeng,Gridnev, Ilya D.,Zhang, Wanbin
, p. 11505 - 11512 (2019/07/17)
In order to effectively synthesize chiral α-amino aldehydes, which have a wide range of potential applications in organic synthesis and medicinal chemistry, a highly chemo- and enantioselective hydrogenation of α-formyl enamides has been developed, catalyzed by a rhodium complex of a P-stereogenic bisphosphine ligand. Under different hydrogen pressures, the chiral α-amido aldehydes and β-amido alcohols were obtained in high yields (97–99 %) and with excellent chemo- and enantioselectivities (up to >99.9 % ee). The hydrogenation can be carried out on a gram scale and with a high substrate/catalyst ratio (up to 20 000 S/C), and the hydrogenated products were further converted into several important chiral products. Computations of the catalytic cycle gave a clear description for the R/S pathways, provided a reasonable explanation for the enantioselectivity, and revealed several other specific features.
Cobalt-Catalyzed Enantioselective Negishi Cross-Coupling of Racemic α-Bromo Esters with Arylzincs
Liu, Feipeng,Zhong, Jiangchun,Zhou, Yun,Gao, Zidong,Walsh, Patrick J.,Wang, Xueyang,Ma, Sijie,Hou, Shicong,Liu, Shangzhong,Wang, Minan,Wang, Min,Bian, Qinghua
, p. 2059 - 2064 (2018/02/14)
The first cobalt-catalyzed enantioselective Negishi cross-coupling reaction, and the first arylation of α-halo esters with arylzinc halides, are disclosed. Employing a cobalt-bisoxazoline catalyst, various α-arylalkanoic esters were synthesized in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield). A diverse range of functional groups, including ether, halide, thioether, silyl, amine, ester, acetal, amide, olefin and heteroaromatics is tolerated by this method. This method was suitable for gram-scale reactions, enabling the synthesis of (R)-xanthorrhizol with high enantiopurity. Radical clock experiments support the intermediacy of radicals.
Bis(oxazoline)titanium complexes as chiral catalysts for enantioselective hydrosilylation of ketones - A combined experimental and theoretical investigation
Bandini, Marco,Bernardi, Fernando,Bottoni, Andrea,Cozzi, Pier Giorgio,Miscione, Gian Pietro,Umani-Ronchi, Achille
, p. 2972 - 2984 (2007/10/03)
A combined experimental and theoretical investigation has been carried out on a new catalytic system, based on bis-(oxazoline) (BOX) complexes of titanium. These catalytic species are able to reduce aromatic ketones with good enantiomeric excesses and satisfactory yields. The experimental and the computational (DFT) evidence has provided useful information on the nature of the active catalytic species and on the mechanism of the reaction. The most likely reaction path involves a TiIV catalytic species. This result agrees with experimentally obtained evidence that seems to rule out the presence of TiIII species. The analysis of the structure of the transition state corresponding to the reduction process (the addition of the hydride to the carbonyl system), provides an interesting insight on the enantioselectivity that characterizes this reaction. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Asymmetric copper complex and cyclopropanation reaction using the same
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, (2008/06/13)
There are disclosed asymmetric copper complex comprising, as components, (a) an optically active bisoxazoline compound of formula (1): wherein R1 and R2 are different and each represent a hydrogen atom, an alkyl group, a cycloalkyl group, or a phenyl or aralkyl group which may be substituted, R3 and R4 each represent a hydrogen atom, an alkyl group, a cycloalkyl group, or a phenyl or aralkyl group which may be substituted, or R3 and R4 may be bonded to each other to form a C3-5 cyclic alkylene group, R5 represents a hydrogen atom or a C1-6 alkyl group, or the two R5 groups may be bonded to each other to represent a C3-5 cyclic alkylene group, (b) a monovalent or divalent copper compound, and (c) a strong acid or a Lewis acid or a mixture thereof, and a process for producing an optically active cyclopropanecarboxylate using the same.
C2-Symmetric 4,4',5,5'-Tetrahydrobi(oxazoles) and 4,4',5,5'-Tetrahydro-2,2'-methylenebis as Chiral Ligands for Enantioselective Catalysis
Mueller, Dieter,Umbricht, Gisela,Weber, Beat,Pfaltz, Andreas
, p. 232 - 240 (2007/10/02)
The synthesis of a series of enantiomerically pure, C2-symmetric 4,4',5,5'-tetrahydro-2,2'-methylene-bis and 4,4',5,5'-tetrahydro-2,2'-bi(oxazoles) is reported.Copper complexes with anionic tetrahydromethylenebis ligands are efficient c
Asymmetric catalytic cyclopropanation of olefins: Bis-oxazoline copper complexes
Lowenthal, Richard E.,Abiko, Atsushi,Masamune, Satoru
, p. 6005 - 6008 (2007/10/02)
Bis-oxazolines (1-7) prepared from diethyl malonate and chiral amino alcohols were converted into their Cu(II) complexes which, upon activation, exhibit high enantioselectivity of up to 99 %ee for catalytic cyclopropanation of olefins.
