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.

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.

Some alkali metal alkyl amides as alkyne isomerization reagents: selective isomerization of one triple bond of a diynol

1983 ◽  
Vol 61 (6) ◽  
pp. 1073-1076 ◽  
Author(s):  
Suzanne R. Abrams ◽  
Donato D. Nucciarone ◽  
Warren F. Steck
Keyword(s):  
Sex Pheromone ◽  
Alkali Metal ◽  
Sodium Salt ◽  
Triple Bond ◽  
Lithium Salt ◽  
Terminal Position ◽  
Sodium Salts ◽  
Triple Bonds ◽  
High Yields ◽  
Insect Sex

The lithium and sodium salts of 1,2-diaminoethane, 1,3-diaminopropane, n-butylamine, and the lithium salt of isobutylamine were studied as potential reagents for isomerization of triple bonds in alkyn-1-ols. The sodium salts of the diamines afforded high yields of the ω-alkyn-1-ol. Somewhat surprisingly, the sodium salt of n-butylamine also effects isomerization to the terminal position. The lithium salt of 1,3-diaminopropane gave the highest conversion of 2- to 3-alkyn-1-ol. A novel, selective rearrangement of one triple bond of a diynol, a 2, ω- to 3, ω-diyn-1-ol isomerization, was incorporated into a synthesis of the insect sex pheromone 3,13-octadecadienol acetate.

Cleavage of BN triple bonds by main group reagents

2018 ◽  
Vol 54 (59) ◽  
pp. 8210-8213 ◽  
Author(s):  
Lena Winner ◽  
Alexander Hermann ◽  
Guillaume Bélanger-Chabot ◽  
Oscar F. González-Belman ◽  
J. Oscar C. Jiménez-Halla ◽  
...  
Keyword(s):  
Triple Bond ◽  
Main Group ◽  
Triple Bonds

A silylene and a 1,2-diaminoalkyne respectively cleave the strong BN triple bond in iminoboranes.

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

Intramolecular Addition of a Dimethylamino C(sp3)–H Bond across C–C Triple Bonds using IrCl(DTBM-SEGPHOS)(ethylene) Catalyst: Synthesis of Indoles from 2-Alkynyl-N-methylanilines

Synthesis ◽  
2021 ◽  
Author(s):  
Toshimichi Ohmura ◽  
Kaito Yagi ◽  
Takeru Torigoe ◽  
Michinori Suginome
Keyword(s):  
Double Bond ◽  
Triple Bond ◽  
Iridium Complex ◽  
Dimethylamino Group ◽  
Catalyst Synthesis ◽  
Double Bond Isomerization ◽  
Triple Bonds ◽  
High Yields

Intramolecular addition of a C(sp3)–H bond of a dimethylamino group across a C–C triple bond in 2-alkynyl-N,N-dimethylanilines was effectively catalyzed by a new iridium complex IrCl(DTBM-SEGPHOS)(C2H4) in mesitylene at 150 °C. The intramolecular C(sp3)–H addition was followed by double bond isomerization to afford 3-substituted indoles in good to high yields.

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