- Nickel-Catalyzed Multicomponent Coupling: Synthesis of α-Chiral Ketones by Reductive Hydrocarbonylation of Alkenes
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A nickel-catalyzed, multicomponent regio- and enantioselective coupling via sequential hydroformylation and carbonylation from readily available starting materials has been developed. This modular multicomponent hydrofunctionalization strategy enables the straightforward reductive hydrocarbonylation of a broad range of unactivated alkenes to produce a wide variety of unsymmetrical dialkyl ketones bearing a functionalized α-stereocenter, including enantioenriched chiral α-aryl ketones and α-amino ketones. It uses chiral bisoxazoline as a ligand, silane as a reductant, chloroformate as a safe CO source, and a racemic secondary benzyl chloride or an N-hydroxyphthalimide (NHP) ester of a protected α-amino acid as the alkylation reagent. The benign nature of this process renders this method suitable for late-stage functionalization of complex molecules.
- Chen, Jian,Zhu, Shaolin
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supporting information
p. 14089 - 14096
(2021/09/13)
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- Dynamic Kinetic Resolution of N-Protected Amino Acid Esters via Phase-Transfer Catalytic Base Hydrolysis
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Asymmetric base hydrolysis of α-chiral esters with synthetic small-molecule catalysts is described. Quaternary ammonium salts derived from quinine were used as chiral phase-transfer catalysts to promote the base hydrolysis of N-protected amino acid hexafluoroisopropyl esters in a CHCl3/NaOH (aq) via dynamic kinetic resolution, providing the corresponding products in moderate to good yields (up to 99%) with up to 96:4 er. Experimental and computational mechanistic studies using DFT calculation and pseudotransition state (pseudo-TS) conformational search afforded a TS model accounting for the origin of the stereoselectivity. The model suggested π-stacking and H-bonding interactions play essential roles in stabilizing the TS structures.
- Yamamoto, Eiji,Wakafuji, Kodai,Furutachi, Yuho,Kobayashi, Kaoru,Kamachi, Takashi,Tokunaga, Makoto
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p. 5708 - 5713
(2018/05/30)
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- Bifunctional squaramide-catalyzed synthesis of chiral dihydrocoumarins via ortho-quinone methides generated from 2-(1-tosylalkyl)phenols
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A bifunctional squaramide-catalyzed reaction of azlactones with o-quinone methides in situ generated from 2-(1-tosylalkyl)-phenols has been successfully developed under basic conditions, providing an efficient and mild access to chiral dihydrocoumarins bearing adjacent tertiary and quaternary stereogenic centers in high yields with excellent diastereo- and enantioselectivities.
- Zhou, Ji,Wang, Mao-Lin,Gao, Xiang,Jiang, Guo-Fang,Zhou, Yong-Gui
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supporting information
p. 3531 - 3534
(2017/03/30)
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- Palladium-catalyzed amidocarbonylation improved by recyclable ionic liquids
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Two types of ionic liquids (halide anion ionic liquids and Brensted acidic ionic liquids) were first applied to improve the palladium-catalyzed amidocarbonylation. Both the palladium catalyst and the ionic liquids could be recycled at least five times without significant loss in catalytic activity. Georg Thieme Verlag Stuttgart.
- Zhu, Bingchun,Jiang, Xuanzhen
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p. 2795 - 2798
(2008/02/11)
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- METHOD OF AMIDOCARBONYLATION REACTION
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A novel method of an amidocarbonylation reaction among an aldehyde compound, an amide compound, and carbon monoxide, which comprises using a palladium-supporting crosslinked-polymer composition containing palladium clusters having a major-axis length of 20 nm or shorter to conduct the amidocarbonylation reaction. Thus, an N-acyl-±-amino acid can be more efficiently and selectively synthesized in a clean reaction system. Also provided is a catalyst for use in the method.
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Page/Page column 11
(2008/06/13)
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- Efficient synthesis of N-acyl-α-amino acids via polymer incarcerated palladium-catalyzed amidocarbonylation
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A novel polymer incarcerated Pd catalyst (PI Pd 7c) was synthesized from amide-containing polymer 6b, and this catalyst was shown to be effective in amidocarbonylation, which is a versatile one-pot method for the preparation of N-acyl-α-amino acids. The reactions proceeded smoothly with a wide variety of substrates, and no leaching of the Pd metal to the reaction mixture was detected.
- Akiyama, Ryo,Sagae, Takahiro,Sugiura, Masaharu,Kobayashi, Shu
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p. 3806 - 3809
(2007/10/03)
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- Platinum-catalyzed amidocarbonylation
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The first example of platinum-catalyzed amidocarbonylation of aldehydes with amides and carbon monoxide is described. In contrast to precedent palladium catalysis, a remarkable ligand acceleration by phosphines was observed. Furthermore, an optically active N-acetyl amino acid was partially epimerized under the platinum-catalyzed conditions, while faster racemization was observed under the palladium catalysis.
- Sagae, Takahiro,Sugiura, Masaharu,Hagio, Hiroyuki,Kobayashi, Shu
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p. 160 - 161
(2007/10/03)
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- Practical and convenient enzymatic synthesis of enantiopure α-amino acids and amides
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Catalyzed by the nitrile hydratase and the amidease in Rhodococcus sp. AJ270 cells under very mild conditions, a number of α-aryl- and α-alkyl-substituted DL-glycine nitriles 1 rapidly underwent a highly enantioselective hydrolysis to afford D-(-)-α-amino acid amides 2 and L-(+)-α-amino acids 3 in high yields with excellent enantiomeric excesses in most cases. The overall enantioselectivity of the biotransformations of nitriles originated from the combined effects of a high L-enantioselective amidase and a low enantioselective nitrile hydratase. The influence of the substrates on both reaction efficiency and enantioselectivity was also discussed in terms of steric and electronic effects. Coupled with chemical hydrolysis of D-(-)-α-phenylglycine amide, biotransformation of DL-phenylglycine nitrile was applied in practical scale to produce both D- and L-phenylglycines in high optical purity.
- Wang, Mei-Xiang,Lin, Shuang-Jun
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p. 6542 - 6545
(2007/10/03)
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- A new improved palladium-catalyzed amidocarbonylation
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A new and improved variant of the palladium-catalyzed amidocarbonylation to yield N-acyl-α-amino acids is described. Using Pd/C as catalyst the products were prepared in good to excellent yields (up to 98 %). Advantages of the Pd/C-catalyst with regard to former catalyst systems are demonstrated by the preparation of N-substituted non-natural amino acids which are of current interest as structural units of peptoids.
- Beller, Matthias,Moradi, Wahed A.,Eckert, Markus,Neumann, Helfried
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p. 4523 - 4526
(2007/10/03)
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- First amidocarbonylation with nitriles for the synthesis of N-acyl amino acids
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A new and efficient one-pot synthesis of N-acyl-α-amino acids by amidocarbonylation is described. Starting from aldehydes, nitriles and carbon monoxide in the presence of acid and palladium catalysts the desired N-acyl amino acids are obtained in good yie
- Beller,Eckert,Moradi
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p. 108 - 110
(2007/10/03)
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