Enantioselective chlorination of β-keto esters and amides catalyzed by chiral copper(II) complexes of squaramide-linked bisoxazoline ligand

Jia, Sheng‐Jian; Du, Da‐Ming

doi:10.1016/j.cclet.2014.06.023

Cited by 12 publications

(3 citation statements)

References 54 publications

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“…Typically, the weakly basic metal acetate complexes showed greater catalyst activity than those complexes prepared from neutral metal chlorides or Lewis acidic metal salts. Other chiral ligands were also examined for applicability to the Zn(OAc) 2 -catalyzed reaction (entries [11][12][13][14]. The trinuclear-aminoiminoBINOL (L2)-Zn 3 (OAc) 4 complex, which possessed outstanding catalytic activity for the iodolactonization reaction, gave 2a in 41% yield with 21% ee (entry 11) [31,32].…”

Section: Resultsmentioning

confidence: 99%

“…Asymmetric chlorination of β-ketoesters was described by Togni et al using a Lewis acid catalyst TiCl 2 (TADDOLato) in 2000 [3,4]. After seminal work by Jørgensen's bisoxazoline-copper catalysis [5], various metal-catalyzed enantioselective chlorinations of β-ketoesters have been developed using Cu [6][7][8][9][10][11][12][13], Ni [14], Co [15], Zn [10], Pd [16], and Fe [17]. The use of Cu and Zn salts for a single chiral ligand allows a switch in enantioselectivity [10].…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Asymmetric Chlorination of β-Ketoesters Using N-PFB-PyBidine-Zn(OAc)2

Suzuki

Kuwano

et al. 2020

Catalysts

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A PyBidine-Zn(OAc)2 complex catalyzed asymmetric chlorination of β-ketoesters. With assistance of NaHCO3, a newly developed N-pentafluorobenzyl-PyBidine (N-PFB-PyBidine)-Zn(OAc)2 catalyst promoted the reaction of α-benzyl-β-ketoesters with N-chlorosuccinimide (NCS) to give the chlorinated products with up to 82% ee. Results of a mechanistic study suggested that zinc-enolate of β-ketoesters was formed on the basic (N-PFB-PyBidine)-Zn(OAc)2 catalyst. The α-chlorinated-β-ketoester was successfully transformed into the chiral epoxide through sequential asymmetric chlorination/cyano-epoxidation in a one-pot synthesis.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catalytic Asymmetric Chlorination of β-Ketoesters Using N-PFB-PyBidine-Zn(OAc)2

Suzuki

Kuwano

et al. 2020

Catalysts

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“…The product 3b was obtained in 92% yield. Other products 3a , 3c , and 3d were also prepared from the corresponding chiral amino alcohols in the similar procedure in good yields up to 95% ,− (Figures S9–S16).…”

Section: Methodsmentioning

confidence: 97%

Synthesis of Chiral Allylic Esters by Using the New Recyclable Chiral Heterogeneous Oxazoline-Based Catalysts

2020

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A new class of recyclable supported chiral heterogeneous ligands has been synthesized by the reaction of functionalized mesoporous SBA-15 with aliphatic- and aromatic-substituted chiral amino oxazoline ligands. The obtained chiral heterogeneous ligands were characterized by several techniques such as Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and BET–BJH. The application of these new heterogeneous ligands in copper-catalyzed asymmetric allylic oxidation of olefins by using perester showed better yields up to 95% and better enantioselectivities up to 96% compared to the corresponding homogeneous catalysts. These findings can be considered as an important step in the advancement of green chemistry. Investigation of the recyclability of the catalysts confirmed that they were easily recovered and reused eight times without significant losses in reactivity, yield, and enantioselectivity.

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Copper‐based Chiral Lewis Acids

Iyanar

Sibi

2017

Chiral Lewis Acids in Organic Synthesis

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Enantioselective chlorination of β-keto esters and amides catalyzed by chiral copper(II) complexes of squaramide-linked bisoxazoline ligand

Cited by 12 publications

References 54 publications

Catalytic Asymmetric Chlorination of β-Ketoesters Using N-PFB-PyBidine-Zn(OAc)2

Catalytic Asymmetric Chlorination of β-Ketoesters Using N-PFB-PyBidine-Zn(OAc)2

Synthesis of Chiral Allylic Esters by Using the New Recyclable Chiral Heterogeneous Oxazoline-Based Catalysts

Copper‐based Chiral Lewis Acids

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