scholarly journals Asymmetric Synthesis of Tetrahydrobenzofurans and Annulated Dihydropyrans via Cooperative One-Pot Organo- and Silver-Catalysis

Synthesis ◽  
2016 ◽  
Vol 48 (19) ◽  
pp. 3207-3216 ◽  
Author(s):  
Uğur Kaya ◽  
Pankaj Chauhan ◽  
Kristina Deckers ◽  
Rakesh Puttreddy ◽  
Kari Rissanen ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Catalyst Loading ◽  
One Pot ◽  
Silver Catalysis ◽  
Asymmetric Michael Addition ◽  
Low Catalyst Loading

A low catalyst loading of a squaramide (0.5 mol%) and a silver(I) salt (1 mol%) efficiently catalyzes a one-pot asymmetric Michael addition/hydroalkoxylation reaction between 1,3-diketones and alkyne-tethered nitroalkenes. Depending on the 1,3-dicarbonyl substrate this cooperative catalytic approach opens access to tetrahydrobenzofurans or annulated dihydropyrans in moderate to excellent yields and very good to excellent enantioselectivities.

scholarly journals Efficient Asymmetric Synthesis of Prostaglandin E1

2007 ◽  
Vol 62 (4) ◽  
pp. 556-560 ◽  
Author(s):  
Jae-Chul Jung ◽  
Oee-Sook Park
Keyword(s):  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Prostaglandin E1 ◽  
Simple Synthesis ◽  
High Yield ◽  
Prostaglandin E ◽  
Magnesium Bromide ◽  
One Pot ◽  
Asymmetric Michael Addition ◽  
Key Steps

A simple synthesis of prostaglandin E1 (PGE1) is described. The key steps are an asymmetric Michael addition to establish the desired (R)-configurations at C8 and C12 of the 2- (trimethylsilyl)ethoxymethyl- (SEM) protected PGE1 and its one-pot deprotection with magnesium bromide in high yield. This method is potentially useful for the preparation of other modified prostaglandins.

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.

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 %).

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.

Silica-supported ZnCl2 — A highly active and reusable heterogeneous catalyst for the one-pot synthesis of dihydropyrimidinones–thiones

2007 ◽  
Vol 85 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Raman Gupta ◽  
Monika Gupta ◽  
Satya Paul ◽  
Rajive Gupta
Keyword(s):  
Zinc Chloride ◽  
Biginelli Reaction ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
One Pot ◽  
Highly Active ◽  
Chloride Catalyst ◽  
Biginelli Compounds ◽  
The One ◽  
Low Catalyst Loading

A novel silica-supported zinc chloride catalyst was prepared and investigated for the Biginelli reaction. The key features of the catalyst include rapid reaction with 100% conversion of aldehyde, good catalyst recyclability, and high stability under the reaction conditions (passes hot filtration test successfully). A low catalyst loading (12 mol% of ZnCl2) was required to achieve a quantitative reaction. Other catalysts such as SiO2–AlCl2, SiO2–AlCl2–ZnCl2 were also prepared and their activity was compared with SiO2–ZnCl2 for the Biginelli reaction.Key words: silica gel, zinc chloride, Biginelli compounds, heterogeneous catalysis, reusability.

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.

scholarly journals Asymmetric Michael addition using sugar derived organocatalysts

2017 ◽  
Vol 17 (4) ◽  
pp. 182-196
Author(s):  
P.B. Lalthanpuii ◽  
C. Lalhriatpuia ◽  
K. Vanlaldinpuia
Keyword(s):  
Molecular Weight ◽  
Asymmetric Synthesis ◽  
Present Article ◽  
Asymmetric Catalysis ◽  
Michael Addition ◽  
Metal Contamination ◽  
Low Molecular Weight ◽  
Asymmetric Transformations ◽  
Asymmetric Michael Addition ◽  
Different Types

Sugars are low-molecular-weight carbohydrates which consist of polyhydroxyl and carbonyl (aldehyde or ketone) functional groups. Different types of compounds derived from sugars have been used extensively as powerful and effective catalysts for asymmetric synthesis. They are readily available at a reasonable price, easily prepared, no metal contamination and are inert towards moisture and air. They are highly functionalized and have well defined stereogenic centres. Most of them are employed as chiral ligands in metal based asymmetric catalysis and are used for various asymmetric transformations. Different compounds derived from sugars have also been used recently as organocatalysts for asymmetric synthesis. The present article provides some of the organocatalysts used for asymmetric synthesis.

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.

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