Water enables an asymmetric cross reaction of α-keto acids with α-keto esters for the synthesis of quaternary isotetronic acids

2019 ◽  
Vol 55 (85) ◽  
pp. 12813-12816 ◽  
Author(s):  
Ping Chen ◽  
Kai Wang ◽  
Boyu Zhang ◽  
Wengang Guo ◽  
Yan Liu ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Cross Reaction ◽  
Asymmetric Aldol ◽  
Keto Esters ◽  
Keto Acids

A water promoted asymmetric aldol/lactonization/enolization cascade reaction of α-keto acids and α-keto esters affords chiral quaternary isotetronic acids with excellent enantioselectivity.

scholarly journals Sustainable synthesis of 3-substituted phthalides via a catalytic one-pot cascade strategy from 2-formylbenzoic acid with β-keto acids in glycerol

2017 ◽  
Vol 13 ◽  
pp. 1425-1429 ◽  
Author(s):  
Lina Jia ◽  
Fuzhong Han
Keyword(s):  
Natural Products ◽  
Cascade Reaction ◽  
Catalytic Process ◽  
Efficient Synthesis ◽  
One Pot ◽  
Keto Acids ◽  
Synthesis Strategy ◽  
Therapeutic Activities

Background: Phthalides are privileged constituents of numerous pharmaceuticals, natural products and agrochemicals and exhibit several biological and therapeutic activities. Therefore, the development of new, facile, and sustainable strategies for the construction of these moieties is highly desired. Results: A broad substrate scope for β-keto acids was found to be strongly compatible with this catalytic process, affording a wide variety of 3-substituted phthalides in good to excellent yields. Conclusion: A concise and efficient synthesis strategy of 3-substituted phthalides from 2-formylbenzoic acid and β-keto acids via a catalytic one-pot cascade reaction in glycerol has been accomplished.

The Retro-Michael Reaction of 1,5-Dicarbonyl Compounds: Scope and Limitation

1999 ◽  
Vol 64 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Jian-Xin Wang ◽  
Tong-Shuang Li
Keyword(s):  
Good Yield ◽  
Steam Distillation ◽  
Michael Reaction ◽  
Glass Wool ◽  
Dicarbonyl Compounds ◽  
Keto Esters ◽  
Tricyclic Compounds ◽  
Keto Acids

Under catalysis of NaOH or KOH adsorbed on glass wool and by using steam distillation, (20R,S)-4,4,5,14-tetramethyl-18,19-dinor-13,17-seco-5β,8α,9β,10α,14β-cholestane-13,17-dione (1) and 3,14-dioxo-14,15-seco-5α-cholestan-15-al (4) gave good yield (>59%) of the corresponding tricyclic compounds (8a, 8b and 10a) via a retro-Michael reaction at 250 °C. While 5-oxo-4-nor-3,5-secocholestan-3-oic acid (6) and ethyl 5-oxo-4-nor-3,5-secocholestan-3-oate (7) afforded low yield (<15%) of the retro-Michael cleavage products (12a, 12b) at the same conditions. Thus, the retro-Michael reaction worked well for 1,5-diketones and 1,5-keto aldehydes but gave poor yield for 1,5-keto esters and 1,5-keto acids.

ChemInform Abstract: Chiral N,N′-Dioxide-Yttrium Triflate Complexes-Catalyzed Asymmetric Aldol Cyclization of α-Keto Esters with α-Isothiocyanato Imide.

ChemInform ◽  
2014 ◽  
Vol 45 (16) ◽  
pp. no-no
Author(s):  
Xiaohu Zhao ◽  
Mingsheng Xie ◽  
Xiaohua Liu ◽  
Yulong Zhang ◽  
Xiao Xiao ◽  
...  
Keyword(s):  
Asymmetric Aldol ◽  
Keto Esters ◽  
Aldol Cyclization

Crown ether catalysis of decarboxylation and decarbalkoxylation of β-keto acids and malonates: a synthetic application

1980 ◽  
Vol 58 (21) ◽  
pp. 2271-2277 ◽  
Author(s):  
Duncan H. Hunter ◽  
Vijay Patel ◽  
Richard A. Perry
Keyword(s):  
Crown Ether ◽  
Remarkable Difference ◽  
Potassium Salts ◽  
One Pot ◽  
Keto Esters ◽  
Step Procedure ◽  
Keto Acids ◽  
Synthetic Application ◽  
Sodium And Potassium

The effect of 18-crown-6 ether on the decarboxylation rates of the sodium and potassium salts of 3-camphorcarboxylic acid 1 and of 1-carbomethoxy-1-carboxycyclohexane 2 was studied. For 2 the K-18C6 salt reacted ca. 104 times faster than the parent acid. This remarkable difference in reactivity was used in developing a one-pot, two-step procedure for decarbalkoxylation of malonic esters. This procedure was then applied to a range of malonates, β-keto esters, and an α-cyano ester. The effect of 15C5, other cations, and good nucleophiles was also studied.

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