764-93-2Relevant articles and documents
Synthesis of acetylenes via dehydrobromination using solid anhydrous potassium phosphate as the base under phase-transfer conditions
Shenawi-Khalil, Sanaa,Sonavane, Sachin U.,Sasson, Yoel
, p. 2295 - 2297 (2012/07/27)
Phase-transfer catalyzed preparation of acetylenes from the corresponding vicinal dibromo compounds via double dehydrobromination using the mild solid base, anhydrous potassium phosphate, under very mild conditions is reported.
Cross-coupling of nonactivated alkyl halides with alkynyl grignard reagents: A nickel pincer complex as the catalyst
Vechorkin, Oleg,Godinat, Aurélien,Scopelliti, Rosario,Hu, Xile
supporting information; experimental part, p. 11777 - 11781 (2012/01/19)
In a pinch: The nickel pincer complex 1 catalyzes the cross-coupling of the title compounds with remarkable substrate scope and functional group tolerance. A nickel/alkynyl species was isolated and shown to be catalytically competent. THF=tetrahydrofuran, O-TMEDA=bis[2-(N,N-dimethylaminoethyl)] ether. Copyright
Weakly nucleophilic conjugate bases of superacids as powerful nucleophiles in vinylic bimolecular nucleophilic substitutions of simple β- alkylvinyl(aryl)-λ3-bromanes
Ochiai, Masahito,Okubo, Takuji,Miyamoto, Kazunori
, p. 3342 - 3344 (2011/05/04)
We report herein, for the first time, the stereoselective synthesis of simple (E)-β-alkylvinyl(aryl)-λ3-bromanes via a boron-λ3-bromane exchange reaction and their unique bimolecular nucleophilic substitutions at the vinylic ipso carbon atom under mild conditions. Interestingly, even weakly nucleophilic anions such as conjugate bases of superacids (HBF4, TfOH, Tf2CH 2, Tf3CH, Tf2NH, etc.) function as nucleophiles toward the vinyl-λ3-bromanes. For instance, the vinylic SN2 reaction of (E)-vinyl-λ3-bromanes with potassium bis(triflyl)methanide stereoselectively produced (Z)-vinyloxy oxosulfonium ylides with exclusive inversion of configuration via oxygen attack, while that with potassium bis(triflyl)imide afforded predominantly (Z)-vinyloxysulfoximines. In marked contrast, (E)-β-alkylvinyl- λ3-iodanes do not undergo the vinylic SN2 reaction with these conjugate bases of superacids. The differences between the nucleofugalities of aryl-λ3-iodanyl and aryl- λ3-bromanyl groups (the latter being greater) probably play a pivotal role in these unique reactions.
Formation of conjugated polynaphthalene via Bergman cyclization
Miao, Changcheng,Zhi, Jian,Sun, Shiyuan,Yang, Xi,Hu, Aiguo
experimental part, p. 2187 - 2193 (2011/04/15)
A series of enediyne containing chiral phthalimides were synthesized through Sonogashira coupling reactions. These enediynes were then subjected to thermal Bergman cyclization under vacuum. Polynaphthalenes with pendant chiral groups were obtained and characterized using GPC, IR spectroscopy, NMR spectroscopy, UV-Vis spectroscopy, and photoluminescence analysis. Under properly optimized conditions, the chirality of chiral directing group was maintained according to CD spectra of final products. After removal of chiral directing groups, weak CD signals representative of main chain chirality were visible. Further modification of the structure of the enediyne compounds will facilitate the synthesis of chiral polynaphthalene through this rather simple way. Extension of the Bergman cyclization to polymer chemistry is promising in the construction of novel polymers with rigid polyarene back-bones.
Nucleophilic vinylic substitutions of (Z)-(2-aroyloxyvinyl)phenyl- λ3-iodanes with tetrabutylammonium halides: Vinylic S N2 reactions and ligand coupling on iodine(III)
Ochiai, Masahito,Nishi, Yoshio,Hirobe, Masaya
, p. 1863 - 1866 (2007/10/03)
Treatment of (Z)-(β-benzoyloxyvinyl)phenyl-λ3- iodanes, readily prepared from ethynyl(phenyl)(tetrafluoroborato)- λ3-iodane via stereoselective Michael-type addition of benzoic acids in methanol in the presence of sodium benzoates, with tetrabutylammonium halides in THF at 65°C results in a vinylic SN2 reaction to give the inverted (E)-β-benzoyloxyvinyl halides in high yields.
Claisen rearrangements based on vinyl fluorides
Tranel, Frank,Haufe, Günter
, p. 1593 - 1608 (2007/10/03)
2-Fluoroalk-1-en-3-ols (4), available from terminal alkenes (1) by bromofluorination, subsequent dehydrobromination of the 1-bromo-2-fluoroalkanes (2) to form 2-fluoroalkenes (3) and selenium dioxide mediated allylic oxidation with tert-butylhydroperoxide, undergo Johnson-Claisen rearrangement on treatment with trimethyl orthoacetate to give methyl 4-fluoroalk-4-enoates (7) in high yields. In contrast Ireland-Claisen rearrangement of 3-acetoxy-2-fluorodec-1-ene (9b) with triethylamine and TMSOTf in ether failed. Instead of the expected formation of a carboxylic acid, selective C-silylation of the α-position to the carboxyl group to form 14 occurred. However, Ireland-Claisen rearrangement was successful with corresponding chloroacetates 10 and propionates 11 of four 2-fluoroalk-1-en-3-ols (4) to give 2-chloro-4-fluoroalk- 4-enecarboxylic acids (15) or its 2-methyl derivatives 16, respectively, in moderate yields. These [3,3]-sigmatropic rearrangements are diastereoselective giving trans-configured double bonds, exclusively. Corresponding esters derived from (Z)-2-fluorocyclododec-2-enol (22), did rearrange to yield mixtures of diastereomers much less selectively. Also 2-fluorodec-2-enol (6), which was prepared by rearrangement of 2-fluoro-2-octyloxirane (5) with TMSOTf and triethylamine, was successfully applied as a starting material for [3,3]-sigmatropic rearrangements. The corresponding 3-(1-fluoroethenyl)alkanoic acid derivatives 17 and 18 were formed in moderate yield. 2-Fluoroalk-1-en-3-ol esters prepared in two steps from 2-fluoroalk-1-enes undergo Claisen rearrangements to form 2-substistuted 4-fluoroalk-4-enecarboxylic acids.
Borane-induced radical reduction of 1-alkenyl- and 1-alkynyl-λ3-iodanes with tetrahydrofuran
Ochiai, Masahito,Tsuchimoto, Yoshimi,Hayashi, Takanori
, p. 5381 - 5384 (2007/10/03)
Exposure of 1-alkenyl(phenyl)- and 1-alkynyl(phenyl)-λ3-iodanes to THF at room temperature in the presence of a catalytic amount of trialkylborane results in smooth reduction to give 1-iodo-1-alkenes and 1-iodo-1-alkynes as major products, respectively. The key step in the reductions probably involves a single-electron transfer from α-tetrahydrofuryl radical to the λ3-iodanes, which generates the labile [9-I-2] iodanyl radicals.
Process for the preparation of cyclopropylacetylene
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Page column 14, 17-18, (2008/06/13)
The present invention relates generally to novel methods for the preparation of cyclopropylacetylene which is an essential reagent in the asymmetric synthesis of (S)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one; a useful human immunodeficiency virus (HIV) reverse transcriptase inhibitor with superior anti-retroviral activity. In the process, for example, cyclopropane carboxaldehyde is alkylated to form 1,1,1-trichloro-2-cyclopropyl-ethanol; which in turn undergoes elimination to form 1,1-dichloro-2-cyclopropyl-ethene; which in turn undergoes elimination to form cyclopropyl acetylene.
Process for the preparation of cyclopropylacetylene
-
, (2008/06/13)
The present invention relates generally to novel methods for the synthesis of cyclopropylacetylene which is an essential reagent in the asymmetric synthesis of (S)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one; a useful human immunodeficiency virus (HIV) reverse transcriptase inhibitor. In the process, for example, cyclopropane carboxaldehyde is alkylated to form 1,1,1-trichloro-2-cyclopropyl-ethanol; which in turn is hydroxy protected to form 1,1,1-trichloro-2-cyclopropylethyltosylate; which in turn undergoes elimination to form cyclopropyl acetylene. This improvement provides for high conversion of inexpensive, readily available starting materials into cyclopropylacetylene, high overall yields and can be conducted on an industrial scale.
Stereoselective synthesis of (Z)-enethiols and their derivatives: Vinylic SN2 reaction of (E)-alkenyl(phenyl)-λ3-iodanes with thioamides
Ochiai, Masahito,Yamamoto, Shinji,Suefuji, Takashi,Chen, Da-Wei
, p. 2753 - 2756 (2007/10/03)
(Equation presented) Exposure of (E)-β-alkylvinyl(phenyl)-λ3-iodanes to thioamides in dichloromethane at room temperature was found to result in a bimolecular nucleophilic substitution (SN2) at the vinylic carbon atom to give inverted (Z)-enethiols and/or (Z)-S-vinylthioimidonium salts. Vinylic SN2 reactions with thioureas are also discussed.
