155187-28-3Relevant academic research and scientific papers
Substituent effects on the cyclization mode of 7-sulfonyl-3-hepten-1,5- diynes and 11-sulfonylundeca-3,7-dien-1,5,9-triynes
Wu, Huey-Juan,Lin, Chi-Fong,Lee, Jeng-Lin,Lu, Wen-Der,Lee, Chia-Ying,Chen, Chin-Chau,Wu, Ming-Jung
, p. 3927 - 3934 (2007/10/03)
In probing of cycloaromatization of 7-phenylsulfonyl-3-hepten-1,5-diyne systems to generate biradical intermediates under an alkaline condition suggested that the aryl moiety on C3-C4 also plays an important role to switch the Myers cyclization to Schmitt
An iterative approach to cis-oligodiacetylenes
Kosinski, Christoph,Hirsch, Andreas,Heinemann, Frank W.,Hampel, Frank
, p. 3879 - 3890 (2007/10/03)
Phenyl-terminated cis-oligodiacetylenes such as 18, containing a π-conjugated backbone with four triple and three double bonds, were synthesized using Pd-catalysed Sonogashira coupling reactions. Compound 18 represents the longest cis-oligoenyne system to date, but it suffers from the drawback of cis/trans isomerization observed in solution. In order to avoid cis/trans isomerization in such cis-oligodicacetylenes, the ene moieties within the oligomeric backbone were locked by incorporation into ring systems. 1,2-Dibromocyclopentene was used as an olefinic building block for this purpose, permitting the iterative synthesis of the cis-oligodiacetylenes 27 and 28, possessing the same π-conjugated backbone as 18. Unlike that compound, however, 27 and 28 are stable both in solution and in the solid state. Whereas X-ray crystallography revealed a completely planar structure for 27 in the single crystal, NMR and computational investigations suggest that a preferred helical conformation is likely in solution.
Novel and general cross-coupling reactions of alkynylzinc reagents and organotellurium compounds
Dabdoub, Miguel J.,Dabdoub, Vania B.,Marino, Joseph P.
, p. 437 - 440 (2007/10/03)
The efficient cross-coupling reactions of different alkynyl organozinc reagents with unsaturated organotellurium species catalyzed by Pd(PPh3)4/CuI and using THF/DMF systems are described. These cross-coupling reactions are general and permit the formation of new sp-sp2 carbon-carbon bonds. New reactions to reach the necessary alkynylzinc intermediates were also developed from terminal alkynes or using acetylenic tellurides as starting materials.
Stereoselective hydrogenolysis of 1,1-dibromo-1-alkenes and stereospecific synthesis of conjugated (Z)-alkenyl compounds
Uenishi, Jun'ichi,Kawahama, Reiko,Yonemitsu, Osamu,Tsuji, Jiro
, p. 8965 - 8975 (2007/10/03)
The Pd-catalyzed hydrogenolysis of 1,1-dibromoalkenes with Bu3SnH occurs at room temperature stereoselectively to give (Z)-1-bromo-1-alkenes. We sought to determine the optimal reaction conditions and illustrate the scope of this method with 32 dibromoalkenes including alkenyl- and alkynyl- conjugated 1,1-dibromo-1-alkenes 7a-h and 2,2-disubstituted 1,1-dibromo-1- alkenes 9af. Triphenylphosphine was the best ligand for the Pd-catalyzed hydrogenolysis. A wide range of solvents can be used for this reaction excluding EtOH, AcOH, and CHCl3. However, the reaction proceeds even in these solvents with the addition of a cosolvent or radical scavenger. The reaction of 1,1-diiodo-1-alkene (3) gave a mixture of (Z)-1-iodo-1-alkene (4), (Z)-1-tributylstannyl-1-alkene (5), and a terminal alkene 6, while that of 1,1-dichloroalkene did not occur. This selectivity can be explained by the stereoselective insertion of Pd(0) to a trans bromine-alkenyl carbon bond, successive transmetalation with Bu3SnH, and reductive elimination. The Suzuki and Sonogashira couplings of the resulting (Z)-1-bromo-1-alkenes with alkenyl(dialkoxy)borane and terminal alkyne occurred to give conjugated polyenes and enynes stereospecifically. The Pd-catalyzed hydrogenolysis of 1,1-dibromo-1-alkene and successive cross-coupling can be carried out either in a stepwise manner or in one-pot under the same Pd catalysis. These two processes should be useful for the synthesis of geometrically pure polyene and enyne with a Z-alkenyl unit.
Synthesis of polyphenylene derivatives by thermolysis of enediynes and dialkynylaromatic monomers
John, Jens A.,Tour, James M.
, p. 15515 - 15534 (2007/10/03)
Described are the syntheses of substituted enediynes and dialkynylaromatics using Pd- or Pd/Cu-catalyzed cross coupling procedures. The products were then thermalized to afford the corresponding poly(p- phenylene)s, poly(1,4-naphthalene)s, poly(benzo[c]thiophene)s, and poly(dibenzothiophene)s. Fifteen examples are provided that show the scope of the polymerization process based upon substituent patterns and cyclization moieties. The superb thermal resiliency of the newly derived polymers is demonstrated using thermogravimetric analysis. The polymer structure was generally confirmed using IR data correlations to small molecules that resembled the polymers' repeat unit structure. Radical trapping of dimeric intermediates, that were analyzed by GCMS, further substantiated the proposed mechanistic route. The step-growth polymerization pattern was determined by monitoring the degree of monomer consumption versus the polymer molecular weight.
Stereoselective synthesis of enediynes and enynes by condensation of aldehydes with γ-(trialkylsilyl)allenylboranes
Wang,Wang,Yu Gui Gu
, p. 8391 - 8394 (2007/10/02)
Enediynes and enynes with high geometric purity were synthesized by treating acetylenic and simple aldehydes with γ-(tert- butyldimethylsilyl)allenylborane 2a followed by the elimination step of the Peterson olefination reaction.
