New and Regioselective Synthesis of 4-Ylidene-tetronic Acids by Lewis-Acid Catalyzed Cyclization of 4-Alkoxy-bis-(trimethylsiloxy)-1,3-dienes with Oxalyl Chloride

Synlett ◽  
2000 ◽  
Vol 2000 (06) ◽  
pp. 0844-0846
Keyword(s):  
Lewis Acid ◽  
Oxalyl Chloride ◽  
Regioselective Synthesis ◽  
Acid Catalyzed

Regioselective Synthesis of Maturone via Lewis Acid Catalyzed Deils-Alder Reaction

Heterocycles ◽  
1993 ◽  
Vol 35 (1) ◽  
pp. 33 ◽  
Author(s):  
Ken Kanematsu ◽  
Mariko Aso ◽  
Akio Ojida ◽  
Guang Yang
Keyword(s):  
Lewis Acid ◽  
Alder Reaction ◽  
Regioselective Synthesis ◽  
Acid Catalyzed

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.

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