Electrophilic cyclization of an olefinic β-keto ester

1981 ◽  
Vol 59 (14) ◽  
pp. 2239-2241 ◽  
Author(s):  
Margot Alderdice ◽  
Larry Weiler
Keyword(s):  
Silica Gel ◽  
Aluminum Chloride ◽  
Cyclization Reaction ◽  
Electrophilic Cyclization ◽  
Keto Ester ◽  
Potential Use

Benzeneselenenyl chloride and aluminum chloride or benzenesulphenyl chloride and silica gel initiate an electrophilic cyclization of methyl 7-methyl-3-oxo-7-octenoate to cyclohexyl derivatives. These products of the cyclization reaction have been converted into intermediates of potential use in the synthesis of unusual carotenoids.

Synthesis of Novel Bis-pyrazoles via Electrophilic Cyclization

2019 ◽  
Vol 16 (6) ◽  
pp. 511-516
Author(s):  
Adnan Cetin
Keyword(s):  
13C Nmr ◽  
Cyclization Reaction ◽  
Electrophilic Cyclization ◽  
Pyrazole Derivatives ◽  
Spectral Analyses ◽  
Mass Spectral ◽  
Palladium Catalyzed ◽  
Ft Ir ◽  
Reaction Compound

Efficient steps towards the synthesis of novel (phenyl)(1'-aryl-1,5,5'-triphenyl[3,3'-bi-1Hpyrazol]- 4-yl)methanones 4a-e were developed. The procedure starts from 1-(4-benzoyl-1,5-diphenyl- 1H-3-pyrazolyl)-3-phenyl-2-propyn-1-one (2) which was synthesized by a palladium catalyzed crosscoupling reaction. Compound 2 reacted with various hydrazines to give (E)-(phenyl)[1,5-diphenyl-3- [3-phenyl-1-(2-arylhydrazono)-2-propyn-1-yl]-1H-4-pyrazolyl]methanones E-3a-e. The bis-pyrazole derivatives 4a-e were synthesized from electrophilic cyclization reaction of α,β-acetylenic hydrazones E-3a-e and copper(I) iodide. All synthesized compounds were characterized by FT-IR, 1H, 13C NMR and Mass spectral analyses.

Iodine-mediated regioselective 5-endo-dig electrophilic cyclization reaction of selenoenynes: synthesis of selenophene derivatives

2017 ◽  
Vol 4 (2) ◽  
pp. 277-282 ◽  
Author(s):  
Renan P. Pistoia ◽  
Juliano A. Roehrs ◽  
Davi F. Back ◽  
Gilson Zeni
Keyword(s):  
Cyclization Reaction ◽  
Electrophilic Cyclization ◽  
Cyclization Reactions

Selenoenynes underwent electrophilic cyclization reactions with iodine in the presence of an appropriate nucleophile to give 3-iodo-selenophenes and 3-organoselenyl-selenophenes.

Synthesis of Organochalcogen Propargyl Aryl Ethers and Their Application in the Electrophilic Cyclization Reaction: An Efficient Preparation of 3-Halo-4-Chalcogen-2H-Benzopyrans

2009 ◽  
Vol 74 (9) ◽  
pp. 3469-3477 ◽  
Author(s):  
Benhur Godoi ◽  
Adriane Sperança ◽  
Davi F. Back ◽  
Ricardo Brandão ◽  
Cristina W. Nogueira ◽  
...  
Keyword(s):  
Cyclization Reaction ◽  
Electrophilic Cyclization ◽  
Aryl Ethers

Stereoselective Total Synthesis of Copa and Ylango Sesquiterpenoids: Preparation of (−)-(1S,4S,5R,7R)-1,7-Dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione and(+)-(1R,4S,5S,7S)-1,7-Dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione

1975 ◽  
Vol 53 (19) ◽  
pp. 2827-2837 ◽  
Author(s):  
Edward Piers ◽  
Ronald W. Britton ◽  
M. Bert Geraghty ◽  
Robert J. Keziere ◽  
R. Dean Smillie
Keyword(s):  
Total Synthesis ◽  
Acetyl Chloride ◽  
Ester Hydrolysis ◽  
Keto Acid ◽  
Blocking Group ◽  
Claisen Condensation ◽  
Keto Ester ◽  
Enolate Anion ◽  
Stereoselective Syntheses ◽  
Potential Use

The efficient, stereoselective syntheses of two diastereomeric bicyclo[3.2.1]octadiones (23 and 24) are described and the potential use of these materials for the synthesis of the copa (1–5) and the ylango (7–11) sesquiterpenoids, respectively, is outlined. Conversion of (+)-carvomenthone (26) into the corresponding n-butylthiomethylene derivative 28, followed by alkylation of the latter with ethyl 2-iodopropionate, gave compound 29. Removal of the blocking group from the latter was accompanied by ester hydrolysis and afforded keto acid 30. An efficient intramolecular Claisen condensation of the corresponding ester 31 yielded (−)-(1S,4S,5R,7R)-1,7-dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione(23). Conversion of the known octalone 39 into the cross-conjugated keto aldehyde 41 was accomplished by standard reactions. Treatment of the latter with lithium dimethylcuprate, followed by trapping of the resultant enolate anion with acetyl chloride gave compound 42. Oxidative ozonolysis of this material yielded the keto acid 43. Esterification of the latter, followed by intramolecular Claisen condensation of the resulting keto ester 45, afforded (+)-(1R,4S,5S,7S)-1,7-dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione (24).

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