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 %).

Potassium Hydroxide Catalysed Intermolecular Aza-Michael Addition of 3-Cyanoindole to Aromatic Enones

Synlett ◽  
2017 ◽  
Vol 28 (10) ◽  
pp. 1227-1231 ◽  
Author(s):  
Jingya Yang ◽  
Tianyuan Li ◽  
Hongyan Zhou ◽  
Nana Li ◽  
Dongtai Xie ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Michael Addition ◽  
Potassium Hydroxide ◽  
Michael Reaction ◽  
Pharmaceutical Compounds ◽  
Catalyst Loading ◽  
Good Substrate ◽  
Substrate Tolerance ◽  
High Yields ◽  
Low Catalyst Loading

Indole is one of the utmost important heterocycles as it is an essential nucleus of many pharmaceutical compounds. Its aza-Michael reaction, however, is underdeveloped because of the moiety’s inherent characteristics. Here, a potassium hydroxide catalysed intermolecular aza-Michael reaction of 3-cyanoindole with aromatic enones is described. A variety of chalcone derivatives are well tolerated and afford the corresponding N-adducts in moderate to high yields. The use of a cheap catalyst, low catalyst loading, mild reaction temperature, and good substrate tolerance make this procedure a direct and facile method for the preparation of N1-functionalized indoles.

Highly Enantioselective Michael Addition of Cyclic Diketones to β,γ-Unsaturated α-Keto Esters Catalyzed by Squaramide Organocatalyst

Synthesis ◽  
2022 ◽  
Author(s):  
Zhi-Wei Ma ◽  
Chuan-Chuan Wang ◽  
Quan-Jian Lv ◽  
Xiao-Pei Chen ◽  
Ai-Qin Li ◽  
...  
Keyword(s):  
Michael Addition ◽  
Large Scale ◽  
Catalyst System ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Keto Esters ◽  
Bicyclic Compounds ◽  
Asymmetric Michael Addition ◽  
High Yields ◽  
Low Catalyst Loading

AbstractA new tertiary amine-squaramide organocatalyst has been developed and applied to the asymmetric Michael addition of cyclic diketones to β,γ-unsaturated α-keto esters. The catalyst system performed well with a low catalyst loading of 1 mol% under mild reaction conditions. A series of synthetically and pharmaceutically useful chiral bicyclic compounds were obtained in high yields (up to 97%) with excellent enantioselectivities (up to 99 % ee). Furthermore, this catalytic system can be used efficiently in large-scale reactions with the yields and enantioselectivities being maintained.

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.

Peptidomimetic organocatalysts: efficient Michael addition of ketones onto nitroolefins with very low catalyst loading

RSC Advances ◽  
2014 ◽  
Vol 4 (57) ◽  
pp. 30325-30331 ◽  
Author(s):  
Srivari Chandrasekhar ◽  
Chintakunta Praveen Kumar ◽  
Togapur Pavan Kumar ◽  
Kothapalli Haribabu ◽  
Bharatam Jagadeesh ◽  
...  
Keyword(s):  
Michael Addition ◽  
Michael Reaction ◽  
Catalyst Loading ◽  
Low Catalyst Loading

The syntheses and applications of peptidomimetic triazole-based catalysts are described as efficient organocatalysts in Michael reaction with low loading.

scholarly journals Asymmetric Michael Addition of Malononitrile with Chalcones via Rosin-Derived Bifunctional Squaramide

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 14
Author(s):  
Ning Lin ◽  
Qiu-Xiang Wei ◽  
Li-Hua Jiang ◽  
Yan-Qiu Deng ◽  
Zhen-Wei Zhang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Carbonyl Compounds ◽  
Catalyst Loading ◽  
Facile Synthesis ◽  
Asymmetric Michael Addition ◽  
High Yields ◽  
Experimental Findings

A rosin-derived bifunctional squaramide catalyzed asymmetric Michael addition of malononitrile with chalcones was discovered. This protocol provides a methodology for the facile synthesis of chiral γ-cyano carbonyl compounds in high yields and enantioselectivities (up to 99% yield and 90% ee) with a lower catalyst loading (0.3 mol%). The predominant R-configured adducts were obtained by this organocatalystic reaction, according to the experimental findings.

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.

Enantioselective synthesis of chiral heterocycles containing both chroman and pyrazolone derivatives catalysed by a chiral squaramide

2015 ◽  
Vol 13 (20) ◽  
pp. 5636-5645 ◽  
Author(s):  
Jun-Hua Li ◽  
Da-Ming Du
Keyword(s):  
Michael Addition ◽  
Enantioselective Synthesis ◽  
Catalyst Loading ◽  
Pyrazolone Derivatives ◽  
Low Catalyst Loading

An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to 3-nitro-2H-chromenes afforded chiral heterocycles containing both chroman and pyrazolone derivatives in high to excellent yields (up to 98%) with high enantioselectivities (up to 96%) under very low catalyst loading (0.2 mol%).

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.

scholarly journals Manganese-Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by a Dual “N–H Effect”

2020 ◽  
Author(s):  
Chenguang Liu ◽  
Mingyang Wang ◽  
Shihan Liu ◽  
Yujie Wang ◽  
Yong Peng ◽  
...  
Keyword(s):  
Noble Metal ◽  
Asymmetric Hydrogenation ◽  
High Reactivity ◽  
Catalyst Loading ◽  
Turnover Number ◽  
Noble Metal Catalysts ◽  
Wide Range ◽  
Metal Catalyzed ◽  
High Yields ◽  
Low Catalyst Loading

<p>The first example of non-noble metal-catalyzed asymmetric hydrogenation of aromatic <i>N</i>-heterocycles is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of a wide range of quinolines, affording high yields and excellent enantioselectivities (up to 97% <i>ee</i>). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which was competitive with the activity of most effective noble metal catalysts for this reaction. The high reactivity of the manganese catalyst and a precise regulation of the enantioselectivity were ensured by a dual “N–H” effect of the ligand structure.<u></u></p>

Manganese-Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by pi–pi Interaction

2020 ◽  
Author(s):  
Chenguang Liu ◽  
Mingyang Wang ◽  
Shihan Liu ◽  
Yujie Wang ◽  
Yong Peng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Noble Metal ◽  
Asymmetric Hydrogenation ◽  
Catalyst Loading ◽  
Turnover Number ◽  
Noble Metal Catalysts ◽  
Wide Range ◽  
Metal Catalyzed ◽  
High Yields ◽  
Low Catalyst Loading

<p>The first example of non-noble metal-catalyzed asymmetric hydrogenation of aromatic <i>N</i>-heterocycles is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of a wide range of quinolines, affording high yields and excellent enantioselectivities (up to 97% <i>ee</i>). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which was competitive with the activity of most effective noble metal catalysts for this reaction. The precise regulation of the enantioselectivity were ensured by a p–p interaction.<u></u></p>

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