Chiral α-substituted allylboronates in a one-pot three-component asymmetric allylic alkylation/carbonyl allylation reaction sequence — Applications to the syntheses of (+)-(3R,5R)-3-hydroxy-5-decanolide and (–)-massoialactone

2009 ◽  
Vol 87 (5) ◽  
pp. 650-661 ◽  
Author(s):  
Lisa Carosi ◽  
Dennis G. Hall

The use of different organomagnesium reagents in the copper-catalyzed allylic alkylation of 3-chloropropenyl boronates with chiral phosphoramidite ligands produces the desired α-substituted allylic boronate reagents in high regioselectivity and with modest to high enantioselectivities (up to 96% ee). The size of the incoming alkyl substituent from the organomagnesium reagent was found to impact the yield and selectivity of the allylic alkylation. A one-pot procedure for the preparation of these chiral allylic boronates followed by a Lewis acid (BF3) catalyzed addition to aldehydes delivers the desired allylboration products, homoallylic secondary alcohols, in good yields and very high diastereoselectivity. This three-component reaction methodology was applied to the syntheses of two lactone-containing natural products, (–)-massoialactone and (+)-(3R,5R)-3-hydroxy-5-decanolide. The key step of these syntheses involved the one-pot enantioselective copper-catalyzed allylic alkylation/allylboration reaction with a benzylic aldehyde, and afforded the desired product in 87% yield, 92% ee, and high E/Z selectivity in a ratio of 22:1. Remarkably, the allylic alkylation step of this sequential reaction was performed with a low catalyst loading of 2 mol% on a scale of >15 mmol that can provide multiple grams of the three-component product.

2007 ◽  
Vol 85 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Raman Gupta ◽  
Monika Gupta ◽  
Satya Paul ◽  
Rajive Gupta

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.


2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Mohammad Reza Nazarifar

Cobalt(II) chloride hexahydrate (CoCl2·6H2O) has been found to be an efficient catalyst for the one-pot synthesis of biscoumarin derivatives through a combination of aromatic aldehydes and 4-hydroxycoumarin in aqueous media at 70°C. Several types of aromatic aldehyde, containing electron-withdrawing groups as well as electron-donating groups, were used in the reaction and in all cases the desired products were synthesized successfully. The present approach offers remarkable advantages such as short reaction times, excellent yields, straightforward procedure, easy purification, environment friendliness, and low catalyst loading.


2018 ◽  
Vol 73 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Samaneh Barkhordarion-Mohammadi ◽  
Javad Safaei-Ghomi

AbstractAmino-functionalized CoFe2O4@SiO2 nanoparticles have been used as an efficient catalyst for the preparation of 2,4-diamino-6-arylpyrimidine-5-carbonitrile derivatives by the one-pot reaction of aromatic aldehydes, malononitrile, and guanidine hydrochloride under conventional heating, microwave, and ultrasound irradiations. This method provides several advantages including mild reaction conditions, the reusability of the catalyst and low catalyst loading, and the use of microwave and ultrasonic irradiation as a valuable and powerful tool.


SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.


2015 ◽  
Vol 93 (5) ◽  
pp. 546-549 ◽  
Author(s):  
Ali Reza Karimi ◽  
Meysam Sourinia ◽  
Zeinab Dalirnasab ◽  
Marzie Karimi

Silica sulfuric acid magnetic nanoparticles efficiently catalyze the one-pot, three-component reaction of isatins and malononitrile with dimedone, 1,3-dimethylbarbituric acid or 4-hydroxycoumarin in EtOH–H2O to afford the corresponding spiro[2-amino-4H-pyran-oxindole] derivatives in high yields under ultrasound irradiation at 60 °C. The heterogeneous nanocatalyst could be recovered easily from the reaction mixture using an external magnet and reused many times without significant loss of its catalytic activity.


Author(s):  
Guguloth Veeranna ◽  
Ramesh Balaboina ◽  
Narasimha Swamy Thirukovela ◽  
Ravindhar Vadde

The one-pot three-component reaction of several 2-ketoaldehdyes, secondary amines and terminal alkynes to access 3-aminofurans was proceeded well in [bmim][PF6] using a simple and cheap CuI catalyst. The resulted 3-aminofuran...


2021 ◽  
Vol 18 ◽  
Author(s):  
Nitishkumar S. Kaminwar ◽  
Sunil U. Tekale ◽  
Srinivas L. Nakkalwar ◽  
Rajendra P. Pawar

: Synthesis of isoxazole structural heterocyclic compounds is important due to their wide range of biological activities. In the present article, we report a convenient and easy method for the synthesis of 4-arylmethylidene-3-substituted-isoxazol-5(4H)-ones by the one-pot three-component reaction of aldehydes, β-keto ester, and hydroxylamine hydrochloride cat-alyzed by sulfated tin oxide as a heterogeneous catalyst.


2021 ◽  
Vol 6 (3) ◽  
pp. 222-227
Author(s):  
Krishna A. Bhensdadia ◽  
Prakash L. Kalavadiya ◽  
Nilam H. Lalavani ◽  
Shipra H. Baluja

A novel series of dihydropyrido[2,3-d]pyrimidine derivatives were synthesized by multicomponent domino cyclization via the one-pot three component reaction of 6-amino uracil, substituted aryl aldehydes and N-methyl-1-(methylthio)-2-nitroethenamine in the presence of PTSA 10 mol% as a catalyst. The structures of these synthesized compounds were characterized by spectral analysis. Further the synthesized compounds screened for in vitro antimicrobial activity. Among all the compounds, compound 4b containing flouro substitution exhibited good inhibition against the tested species.


2019 ◽  
Vol 15 ◽  
pp. 1523-1533 ◽  
Author(s):  
András György Németh ◽  
György Miklós Keserű ◽  
Péter Ábrányi-Balogh

A new multicomponent reaction has been developed between isocyanides, sulfur and alcohols or thiols under mild reaction conditions to afford O-thiocarbamates and dithiocarbamates in moderate to good yields. The one-pot reaction cascade involves the formation of an isothiocyanate intermediate, thus a catalyst-free synthesis of isothiocyanates, as valuable building blocks from isocyanides and sulfur is proposed, as well. The synthetic procedure suits the demand of a modern organic chemist, as it tolerates a wide range of functional groups, it is atom economic and easily scalable.


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