ChemInform Abstract: Preparations of Heterocycles by Intramolecular Cyclization of Tellurols and Related Compounds to a Triple Bond

ChemInform ◽  
2010 ◽  
Vol 32 (36) ◽  
pp. no-no
Author(s):  
Haruki Sashida
Keyword(s):  
Intramolecular Cyclization ◽  
Triple Bond ◽  
Related Compounds

A straightforward double intramolecular cyclization of dibenzyl dichalcogenols into a triple bond

Tetrahedron ◽  
2010 ◽  
Vol 66 (27-28) ◽  
pp. 5149-5157 ◽  
Author(s):  
Haruki Sashida ◽  
Mamoru Kaname ◽  
Akemi Nakayama ◽  
Hirokazu Suzuki ◽  
Mao Minoura
Keyword(s):  
Intramolecular Cyclization ◽  
Triple Bond

scholarly journals Reactions of dialkoxycarbenes with tethered triple bonds to form heterocyclic compounds

1997 ◽  
Vol 75 (2) ◽  
pp. 120-128 ◽  
Author(s):  
Karim Kassam ◽  
John Warkentin
Keyword(s):  
Intramolecular Cyclization ◽  
Triple Bond ◽  
Heterocyclic Compounds ◽  
Heterocyclic Ring ◽  
Ring Systems ◽  
Triple Bonds ◽  
Rapid Construction

Dialkoxycarbenes with a tethered triple bond, generated from the corresponding oxadiazolines, undergo an intramolecular cyclization with the tethered alkyne moiety to give 3,3-dialkoxyvinylcarbene/1,3-dipole intermediates. The regioselectivity of the carbene cyclization is highly dependent upon the nature of the alkyne substituent. In the cases where an exocyclic vinylcarbene is generated, the vinylcarbene intermediate can undergo a synthetically useful [3 + 2] cycloaddition with either an appropriate olefin or an alkyne. This approach allows the rapid construction of some interesting heterocyclic ring systems. Keywords: carbene, dialkoxycarbene, vinylogous dialkoxycarbene, heterocycle.

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.

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