ChemInform Abstract: Intramolecular Cyclization of Cationic η4-Diene Complexes of Molybdenum: A New Synthesis of Tetrahydrofurans, Tetrahydropyrans, and Cyclopentanes.

ChemInform ◽  
1990 ◽  
Vol 21 (16) ◽  
Author(s):  
J. S. BAXTER ◽  
M. GREEN ◽  
T. V. LEE
Keyword(s):  
Intramolecular Cyclization ◽  
New Synthesis

Reactions of alkoxyaryloxycarbenes with tethered triple bonds: a new synthesis of substituted benzofurans

1997 ◽  
Vol 75 (9) ◽  
pp. 1256-1263 ◽  
Author(s):  
Karim Kassam ◽  
Paul C. Venneri ◽  
John Warkentin
Keyword(s):  
High Temperatures ◽  
Intramolecular Cyclization ◽  
Triple Bond ◽  
Triple Bonds ◽  
New Synthesis ◽  
Ketene Acetal

Cyclic 3-alkoxy-3-aryloxyvinylcarbenes can be generated by a highly exo-selective intramolecular cyclization of a dioxycarbene onto a tethered triple bond. Like their dialkoxy counterparts, the 3-alkoxy-3-aryloxyvinylcarbene intermediates are capable of interesting reactions. In contrast to 3,3-dialkoxyvinylcarbenes, which undergo a formal [3 + 2] cycloaddition with highly electron-deficient olefins such as benzylidenemalononitrile, 3-alkoxy-3-aryloxyvinylcarbenes undergo a highly diastereoselective [1 + 2] cycloaddition with benzylidenemalononitrile to give cyclopropylketene acetals. At high temperatures, those cyclopropylketene acetals undergo a clean vinylcyclopropane rearrangement in which the stereochemical integrity of the cyclopropane is retained. Keywords: carbene, alkoxyaryloxy, [1 + 2] cycloaddition, ketene acetal, vinylcyclopropane rearrangement, oxadiazoline.

ChemInform Abstract: A New Synthesis of Indoles via Intramolecular Cyclization of o-Alkynyl N,N-Dialkylanilines Promoted by KOt-Bu/DMSO.

ChemInform ◽  
2015 ◽  
Vol 46 (22) ◽  
pp. no-no
Author(s):  
Yan-yan Chen ◽  
Jia-hua Chen ◽  
Niu-niu Zhang ◽  
Lin-miao Ye ◽  
Xue-Jing Zhang ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
New Synthesis

Intramolecular cyclization of bis-α-diazoketones: A new synthesis of γ-tropolone

Tetrahedron ◽  
1974 ◽  
Vol 30 (3) ◽  
pp. 455-458 ◽  
Author(s):  
J. Font ◽  
J. Valls ◽  
F. Serratosa
Keyword(s):  
Intramolecular Cyclization ◽  
New Synthesis

The [2,3]-sigmatropic rearrangement of propargylic sulfonates to allenic sulfones and further applications to oxacycles and dihydrofuranones

2015 ◽  
Author(s):  
◽  
Rama Rao Tata
Keyword(s):  
Intramolecular Cyclization ◽  
Acid Catalysis ◽  
Sigmatropic Rearrangement ◽  
University Of Missouri ◽  
Sulfonyl Chlorides ◽  
New Synthesis ◽  
Sulfinate Esters ◽  
Tandem Cyclization ◽  
The University ◽  
Silver Fluoride

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The scope of [2,3]-sigmatropic rearrangement of propargylic sulfinates to allenic sulfones by silver catalysis was expanded. A series of new propargylic sulfinate esters was generated from a variety of aromatic and heteroaromatic sulfonyl chlorides and their rearrangement to allenic sulfones is reported. In addition, the synthesis of propargylic sulfinate esters containing electron-withdrawing benzenesulfonyl chlorides was optimized and reported. In the course of pursuing a Nazarov cyclization of allenyl vinyl ketones (AVK), we discovered multiple new reactions. Allenyl alcohols underwent an intramolecular cyclization to 2,5-dihydrofurans in the presence of Fetizon's reagent and this process was then optimized using silver fluoride. The methodology was expanded to synthesize higher membered oxacycles also. A tandem cyclization of hydroxypropargylic sulfinate esters to 2,5-hydrofurans was also developed. A new synthesis of a'-hydroxyenones was developed by the oxidation of a-allenyl alcohols with Cr (VI) regents and then extended to synthesize dihydrofuran- 3(2H)-ones by acid catalysis.

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