Lewis Acid-catalyzed Asymmetric Fluorinations of β-Keto Esters: Dramatic Improvement in Enantioselectivity by Changing the Operation Sequence

2008 ◽  
Vol 37 (10) ◽  
pp. 1098-1099 ◽  
Author(s):  
Kazutaka Shibatomi ◽  
Yuya Tsuzuki ◽  
Seiji Iwasa
Keyword(s):  
Lewis Acid ◽  
Dramatic Improvement ◽  
Keto Esters ◽  
Operation Sequence ◽  
Acid Catalyzed

scholarly journals Lewis Acid Catalyzed Enantioselective Hydroxylation Reactions of Oxindoles and β-Keto Esters Using DBFOX Ligand.

ChemInform ◽  
2007 ◽  
Vol 38 (16) ◽  
Author(s):  
Takehisa Ishimaru ◽  
Norio Shibata ◽  
Jun Nagai ◽  
Shuichi Nakamura ◽  
Takeshi Toru ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Keto Esters ◽  
Acid Catalyzed

ChemInform Abstract: Lewis Acid Catalyzed One-Pot Sequential Reaction for the Synthesis of α-Halogenated β-Keto Esters.

ChemInform ◽  
2010 ◽  
Vol 41 (32) ◽  
pp. no-no
Author(s):  
Han-Feng Cui ◽  
Ke-Yan Dong ◽  
Jing Nie ◽  
Yan Zheng ◽  
Jun-An Ma
Keyword(s):  
Lewis Acid ◽  
One Pot ◽  
Sequential Reaction ◽  
Keto Esters ◽  
Acid Catalyzed

Lewis acid-catalyzed one-pot sequential reaction for the synthesis of α-halogenated β-keto esters

2010 ◽  
Vol 51 (17) ◽  
pp. 2374-2377 ◽  
Author(s):  
Han-Feng Cui ◽  
Ke-Yan Dong ◽  
Jing Nie ◽  
Yan Zheng ◽  
Jun-An Ma
Keyword(s):  
Lewis Acid ◽  
One Pot ◽  
Sequential Reaction ◽  
Keto Esters ◽  
Acid Catalyzed

β-KETO ESTERS FROM REACTION OF ETHYL DIAZOACETATE WITH KETONES

1964 ◽  
Vol 42 (6) ◽  
pp. 1333-1340 ◽  
Author(s):  
W. T. Tai ◽  
E. W. Warnhoff
Keyword(s):  
Lewis Acid ◽  
Boron Trifluoride ◽  
Phenyl Group ◽  
Keto Ester ◽  
Ethyl Diazoacetate ◽  
Keto Esters ◽  
Acid Catalyzed ◽  
Diazoacetic Ester

The Lewis acid catalyzed reaction of diazoacetic ester with ketones has been extended. Convenient conditions have been found for the preparation of some pure β-keto esters in fair to good yields by reaction of ethyl diazoacetate with ketones in the presence of boron trifluoride at −40° to −70°. The reaction is apparently general since cyclopentanone, cyclohexanone, and acetophenone gave nearly pure β-keto esters in 44%, 79%, and 38% yields, respectively, based on diazoacetic ester. In the case of acetophenone the phenyl group migrated. Acetone gave 78% of a mixture of β-keto ester and glycidic ester.

Non-Metal Lewis Acid-Catalyzed Cross-Claisen Condensation for β-Keto Esters

2021 ◽  
Author(s):  
Tianyu Zhang ◽  
Zhenkun Yang ◽  
Dapeng Zhou ◽  
Fuliang Meng ◽  
Zhengyu Han ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Claisen Condensation ◽  
Keto Esters ◽  
Acid Catalyzed

In this work, we disclose a new catalytic and high chemoselective cross-Claisen condensation of esters. In the presence of TBSNTf2 as non-metal Lewis acid, various esters can undergo cross-Claisen condensation...

Lewis Acid-Catalyzed Enantioselective Hydroxylation Reactions of Oxindoles and β-Keto Esters Using DBFOX Ligand

2006 ◽  
Vol 128 (51) ◽  
pp. 16488-16489 ◽  
Author(s):  
Takehisa Ishimaru ◽  
Norio Shibata ◽  
Jun Nagai ◽  
Shuichi Nakamura ◽  
Takeshi Toru ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Keto Esters ◽  
Acid Catalyzed

Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Activation ◽  
Lewis Acid Catalysts ◽  
Distinct Mode ◽  
Aliphatic Ketones ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

scholarly journals Comparison of Corn Stover Pretreatments with Lewis Acid Catalyzed Choline Chloride, Glycerol and Choline Chloride-Glycerol Deep Eutectic Solvent

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1170
Author(s):  
Yuan Zhu ◽  
Benkun Qi ◽  
Xinquan Liang ◽  
Jianquan Luo ◽  
Yinhua Wan
Keyword(s):  
Corn Stover ◽  
Lewis Acid ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Enzymatic Saccharification ◽  
Glycerol Solution ◽  
Cellulose Conversion ◽  
Biomass Processing ◽  
Acid Catalyzed ◽  
Highly Correlated

Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.

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