scholarly journals Enantioselective Au(I)-Catalyzed Multicomponent Annulation via Tethered Counterion-Directed Catalysis

2021 ◽  
Author(s):  
Zhenhao Zhang ◽  
Nazarii Sabat ◽  
Gilles Frison ◽  
Angela Marinetti ◽  
Xavier GUINCHARD
Keyword(s):  
Phosphoric Acid ◽  
Dft Calculations ◽  
Multicomponent Reaction ◽  
Multicomponent Reactions ◽  
Aromatic Aldehydes ◽  
Catalyst Loading ◽  
Broad Scope ◽  
Chiral Phosphoric Acid ◽  
High Yields ◽  
Low Catalyst Loading

Gold(I) complexes of a new chiral phosphoric acid functionalized phosphine of the CPA-Phos series enable the enantioselective multicomponent reactions between aldehydes, hydroxylamines and cyclic yne-enones, leading to 3,4-dihydro-1H-furo[3,4-d][1,2]oxazines. This represents the first example of highly enantioselective multicomponent reaction in gold(I) catalysis. The reactions proceed at low catalyst loading, provide high yields, total diastereoselectivity and enantiomeric excesses up to 99%. Silver-free conditions can be applied. The method has a very broad scope, as it applies to both aliphatic and aromatic aldehydes and hydroxylamines, to a variety of cyclic yne-enones, as well as to yne-enone derived oximes. DFT calculations are reported that enlighten the enantiocontrol pathway.

Three-Component Synthesis of 4-Arylidene-3-alkylisoxazol-5(4H)-ones in the presence of potassium 2,5-dioxoimidazolidin-1-ide

2021 ◽  
Vol 25 ◽  
Author(s):  
Neda Reihani ◽  
Hamzeh Kiyani
Keyword(s):  
Ethylene Glycol ◽  
Ethyl Acetoacetate ◽  
Reaction Medium ◽  
Hydroxylamine Hydrochloride ◽  
Aromatic Aldehydes ◽  
Catalyst Loading ◽  
Efficient Synthesis ◽  
Current Process ◽  
High Yields ◽  
Low Catalyst Loading

: An efficient synthesis of 4-arylidene-3-alkylisoxazole-5(4H)-ones has been implemented via the three-component cyclocondensation of aryl(heteroaryl)aldehydes with hydroxylamine hydrochloride and β-ketoesters. The potassium 2,5-dioxoimidazolidin-1-ide has been introduced as the new organocatalyst to facilitate of this heterocyclization. In the current process, three starting materials, including substituted benzaldehydes/heterocyclic aromatic aldehydes, hydroxylamine hydrochloride, and ethyl acetoacetate/propyl acetoacetate/butyryl acetoacetate have been successfully used for the synthesize of the number of substituted isoxazole-5(4H)-ones in good to high yields in ethylene glycol as a green reaction medium at 80 ºC. The low catalyst loading is also a main advantage over the some reported catalysts.

scholarly journals Synthesis of pyrimidines by Fe3O4@SiO2-L-proline nanoparticles

2020 ◽  
Vol 43 (1) ◽  
pp. 117-124
Author(s):  
Javad Safaei-Ghomi ◽  
Zahra Samadi
Keyword(s):  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Catalyst Loading ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
High Yields ◽  
Low Catalyst Loading ◽  
Ft Ir Spectroscopy

AbstractFe3O4@SiO2-L-proline nanoparticles have been used as an effective catalyst for the preparation of pyrimidines by three-component reactions of 1,3-dimethylbarbituric acid, aromatic aldehydes and 4-methyl aniline or 4-methoxy aniline under reflux condition in ethanol. Fe3O4@SiO2-L-proline nanoparticles have been characterized by scanning electronic microscopy (SEM), powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermal gravimetric analysis (TGA), energy dispersive X-ray (EDS), dynamic light scattering (DLS) and FT-IR spectroscopy. This method provides several advantages including, the reusability of the catalyst, low catalyst loading, atom economy, short reaction times and high yields of products.

scholarly journals Camphor-10-sulfonic acid catalyzed condensation of 2-naphthol with aromatic/aliphatic aldehydes to 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes

2014 ◽  
Vol 79 (9) ◽  
pp. 1051-1058 ◽  
Author(s):  
Kshama Kundu ◽  
Sandip Nayak
Keyword(s):  
Microwave Irradiation ◽  
Sulfonic Acid ◽  
Aromatic Aldehydes ◽  
Catalyst Loading ◽  
Alkyl Aryl ◽  
Aliphatic Aldehydes ◽  
Acid Catalyzed ◽  
High Yields ◽  
Low Catalyst Loading ◽  
Sole Product

(?)-Camphor-10-sulfonic acid (CSA) catalyzed condensation of 2-naphthol with both aliphatic/aromatic aldehydes at 80?C yielded 14-alkyl/aryl-dibenzoxanthenes as the sole product in high yields. However, the same condensation with benzaldehyde at 25?C afforded a mixture of intermediate 1,1-bis-(2-hydroxynaphthyl)phenylmethane and 14-phenyl-dibenzoxanthene while the condensation with aliphatic aldehydes at 25?C furnished the corresponding 14-alkyl-dibenzoxanthenes as the sole product. Moreover, condensation of 2-naphthol with aromatic/aliphatic aldehydes with low catalyst loading (2 mol%) was greatly accelerated under microwave irradiation to afford the corresponding 14-aryl/alkyl-dibenzoxanthenes as the sole product in high yields.

scholarly journals Organocatalytic Asymmetric [2 + 4] Cycloadditions of 3-Vinylindoles with ortho-Quinone Methides

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6751
Author(s):  
Si-Jia Liu ◽  
Man-Su Tu ◽  
Kai-Yue Liu ◽  
Jia-Yi Chen ◽  
Shao-Fei Ni ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Structural Diversity ◽  
Quinone Methides ◽  
Chiral Phosphoric Acid ◽  
Catalytic Asymmetric ◽  
High Yields ◽  
Asymmetric Cycloadditions

Catalytic asymmetric [2 + 4] cycloadditions of 3-vinylindoles with ortho-quinone methides and their precursors were carried out in the presence of chiral phosphoric acid to afford a series of indole-containing chroman derivatives with structural diversity in overall high yields (up to 98%), good diastereoselectivities (up to 93:7 dr) and moderate to excellent enantioselectivities (up to 98% ee). This approach not only enriches the chemistry of catalytic asymmetric cycloadditions involving 3-vinylindoles but is also useful for synthesizing chiral chroman derivatives.

Catalytic Asymmetric Substitution Reaction of 3-Substituted 2-Indolylmethanols with 2-Naphthols

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3684-3692
Author(s):  
Feng Gao ◽  
Yu-Chen Zhang ◽  
Feng Shi ◽  
Jin-Ping Lan ◽  
Yi-Nan Lu ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Substitution Reaction ◽  
Enantioselective Synthesis ◽  
Chiral Phosphoric Acid ◽  
Catalytic Asymmetric ◽  
High Yields

A catalytic asymmetric substitution of 3-substituted 2-indolylmethanols with 2-naphthols has been established under the catalysis of chiral phosphoric acid. By this approach, a series of structurally diversified triarylmethane derivatives were obtained in moderate to high yields with good enantioselectivities (up to 97% yield, 95:5 er). This approach not only enriches the chemistry of 2-indolylmethanol-inolved catalytic asymmetric substitutions, but also provides a useful method for the enantioselective synthesis of chiral triarylmethane derivatives.

One-pot multicomponent synthesis of β-acetamidoketones catalysed by pTSA1

2007 ◽  
Vol 85 (7-8) ◽  
pp. 479-482 ◽  
Author(s):  
Biswanath Das ◽  
Kongara Ravinder Reddy ◽  
Yallamalla Srinivas ◽  
Rathod Aravind Kumar
Keyword(s):  
Multicomponent Reaction ◽  
Acetyl Chloride ◽  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Catalytic Amount ◽  
Multicomponent Synthesis ◽  
One Pot ◽  
High Yields ◽  
Three Component Coupling

A catalytic amount of pTSA has been found to be effective to carry out a one-pot three-component coupling of aromatic aldehydes, enolizable ketones or ketoesters, and acetonitrile in the presence of acetyl chloride to afford β-acetamidoketones in high yields. Short reaction times and inexpensive catalyst are main advantages of this protocol.Key words: β-acetamidoketone, pTSA, multicomponent reaction, diastereoselectivity.

scholarly journals Enantioselective Michael addition of 2-hydroxy-1,4-naphthoquinones to nitroalkenes catalyzed by binaphthyl-derived organocatalysts

2012 ◽  
Vol 8 ◽  
pp. 699-704 ◽  
Author(s):  
Saet Byeol Woo ◽  
Dae Young Kim
Keyword(s):  
Michael Addition ◽  
Catalyst Loading ◽  
High Yields ◽  
Low Catalyst Loading

The highly enantioselective Michael addition of 2-hydroxy-1,4-naphthoquinones to nitroalkenes, promoted by binaphthyl-modified chiral bifunctional organocatalysts is described. This reaction afforded the chiral functionalized naphthoquinones in high yields (81–95%) and excellent enantioselectivities (91–98% ee) under low catalyst loading (1 mol %).

Role of keto–enol tautomerization in a chiral phosphoric acid catalyzed asymmetric thiocarboxylysis of meso-epoxide: a DFT study

2015 ◽  
Vol 13 (45) ◽  
pp. 10981-10985 ◽  
Author(s):  
Manjaly J. Ajitha ◽  
Kuo-Wei Huang
Keyword(s):  
Density Functional Theory ◽  
Phosphoric Acid ◽  
Dft Calculations ◽  
Density Functional ◽  
Dft Study ◽  
Functional Theory ◽  
Chiral Phosphoric Acid ◽  
Acid Catalyzed

The mechanism of a chiral phosphoric acid catalyzed thiocarboxylysis of meso-epoxide was investigated by density functional theory (DFT) calculations (M06-2X).

Highly Enantioselective Biginelli Reaction of Aliphatic Aldehydes Catalyzed by Chiral Phosphoric Acids

Synlett ◽  
2017 ◽  
Vol 28 (15) ◽  
pp. 2041-2045 ◽  
Author(s):  
Yongbiao Guo ◽  
Chuanpin Zou ◽  
Zhenhua Gao ◽  
Xiangyan Meng ◽  
Guilan Huang ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Biginelli Reaction ◽  
Aliphatic Aldehyde ◽  
Reaction Conditions ◽  
Aliphatic Aldehydes ◽  
Keto Ester ◽  
Chiral Phosphoric Acid ◽  
Three Component Reaction ◽  
High Yields ◽  
Phosphoric Acids

Several chiral phosphoric acids were evaluated as organocatalysts for the enantioselective Biginelli reaction of aliphatic aldehydes. With a chiral phosphoric acid derived from 3,3′-bis(3,5-di-tert-butyl-4-methoxyphenyl)-1,1′-binaphthalene-2,2′-diol, and after extensive optimization of the reaction conditions, the corresponding dihydropyrimidines were obtained in moderate to high yields with 73–87% ee by a three-component reaction of an aliphatic aldehyde, urea, and a β-keto ester.

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