Lewis acid catalyzed Claisen rearrangement: Regioselective synthesis of oxygen, nitrogen, and sulfur heterocycles

2008 ◽  
Vol 86 (1) ◽  
pp. 72-78 ◽  
Author(s):  
K C Majumdar ◽  
A K Pal
Keyword(s):  
Lewis Acid ◽  
Claisen Rearrangement ◽  
Sigmatropic Rearrangement ◽  
Regioselective Synthesis ◽  
Aluminium Chloride ◽  
Sulfur Heterocycles ◽  
Acid Catalyzed

Regioselective synthesis of pentacyclic heterocycles containing oxygen, nitrogen, and sulfur has been achieved in good to excellent yields by the sequential Claisen rearrangement of but-2-ynyl ethers and sulfides containing quinolone moiety. The substrates ethers and sulfides were prepared from 1-aryloxy-4-chlorobut-2-ynes with N-alkyl-4-hydroxyquinoline-2(1H)-ones.Key words: regioselectivity, [3,3] sigmatropic rearrangement, nucleophilicity of sulfur, aluminium chloride, heterocycles.

Regioselective synthesis of biologically interesting pentacyclic polyheterocycles by sequential thio-Claisen and AlCl3 catalyzed oxy-Claisen rearrangement of 4-(4′-aryloxybut-2′-ynylthio)-1-phenyl-1,8-naphthyridin-2(1H)-one

2006 ◽  
Vol 84 (12) ◽  
pp. 1632-1639 ◽  
Author(s):  
K C Majumdar ◽  
R Islam
Keyword(s):  
Lewis Acid ◽  
Claisen Rearrangement ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Acid Catalyst ◽  
Sigmatropic Rearrangement ◽  
Regioselective Synthesis ◽  
X Ray ◽  
Lewis Acid Catalyst ◽  
Acid Catalyzed

A number of 4-aryloxymethyl-6-phenyl-2H-thiopyrano[3,2-c][1,8]naphthyridin-5(6H)-ones were regio selectively synthesized in 82%–95% yields by the thermal Claisen rearrangement of 4-(4′-aryloxybut-2′-ynylthio)-1-phenyl-[1,8]naphthyridin-2(1H)-ones. These products were then subjected to a second Claisen rearrangement in the presence of a Lewis acid catalyst, anhyd. AlCl3, to give hitherto unreported pentacyclic heterocycles in 75%–90% yields. The same final products were also obtained in low yield upon refluxing 4-aryloxymethyl-6-phenyl-2H-thio pyrano-[3,2-c][1,8]naphthyridin-5(6H)-ones in N,N-diethyl aniline for 12–14 h. This method was found to be more effective than thermal Claisen rearrangement.Key words: [3,3] sigmatropic rearrangement, regioselective synthesis, phase transfer catalysis, sequential Claisen rearrangement, Lewis acid catalyzed Claisen rearrangement, single crystal X-ray.

Development of a New Lewis Acid-Catalyzed [3,3]-Sigmatropic Rearrangement:  The Allenoate-Claisen Rearrangement

2002 ◽  
Vol 124 (46) ◽  
pp. 13646-13647 ◽  
Author(s):  
Tristan H. Lambert ◽  
David W. C. MacMillan
Keyword(s):  
Lewis Acid ◽  
Claisen Rearrangement ◽  
Sigmatropic Rearrangement ◽  
Acid Catalyzed

scholarly journals Development of a New Lewis Acid Catalyzed [3,3]-Sigmatropic Rearrangement: The Allenoate-Claisen Rearrangement.

ChemInform ◽  
2003 ◽  
Vol 34 (10) ◽  
Author(s):  
Tristan H. Lambert ◽  
David W.C. MacMillan
Keyword(s):  
Lewis Acid ◽  
Claisen Rearrangement ◽  
Sigmatropic Rearrangement ◽  
Acid Catalyzed

A Facile Regioselective Synthesis of Tetracyclic Sulfur Heterocycles by Tandem Thio-Claisen Rearrangement.

ChemInform ◽  
2007 ◽  
Vol 38 (39) ◽  
Author(s):  
Krishna C. Majumdar ◽  
Nilasish Pal
Keyword(s):  
Claisen Rearrangement ◽  
Regioselective Synthesis ◽  
Sulfur Heterocycles

Facile Regioselective Synthesis of Benzofuran-Annulated Six-Membered Sulfur Heterocycles and the Occurrence of Thermal [1,3] Sigmatropic Rearrangement

2011 ◽  
Vol 8 (3) ◽  
pp. 176-179 ◽  
Author(s):  
Krishna C. Majumdar ◽  
Sanjay Nath ◽  
Buddhadeb Chattopadhyay ◽  
Krishanu Ray
Keyword(s):  
Sigmatropic Rearrangement ◽  
Regioselective Synthesis ◽  
Sulfur Heterocycles

Synthesis of 4-substituted homoallylic alcohols via a one-pot tandem Lewis-acid catalyzed crotylboration-[3,3]-sigmatropic rearrangement

2005 ◽  
pp. 1988 ◽  
Author(s):  
P. Veeraraghavan Ramachandran ◽  
Debarshi Pratihar ◽  
Debanjan Biswas
Keyword(s):  
Lewis Acid ◽  
Sigmatropic Rearrangement ◽  
One Pot ◽  
Homoallylic Alcohols ◽  
Acid Catalyzed
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