- The Preparation of Unsymmetrical Diacetylenes from Alkenynyl Triflates
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Alkenynyl triflates 5 (alkynylvinyl trifluoromethanesulfonates) are readily converted into unsymmetrical diacetylenes 6 in good yields by the base-initiated elimination of trifluoromethanesulfonic acid.
- Stang, Peter J.,Dixit, Vandana
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- Fritsch-Buttenberg-Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes
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A series of 1-heteroatom-substituted vinyl p-tolyl sulfoxides were prepared and treated with organometallic reagents to evaluate which combination of sulfoxides and organometallic reagents yielded alkynes the most efficiently. The use of 1-chlorovinyl p-tolyl sulfoxide and isopropylmagnesium chloride was optimal for this purpose. A variety of 1-chlorovinyl p-tolyl sulfoxides were prepared from carbonyl compounds and chloromethyl p-tolyl sulfoxide and were converted into alkynes via the sulfoxide/magnesium exchange reaction and subsequent Fritsch-Buttenberg-Wiechell (FBW) rearrangement of the resulting magnesium alkylidene carbenoids. The mechanism of the FBW rearrangement of magnesium alkylidene carbenoids was studied by using13C-labeled sulfoxides and by using DFT calculations.
- Ando, Akane,Imafuji, Aki,Kimura, Tsutomu,Sekiguchi, Koto
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p. 1352 - 1359
(2021/06/06)
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- "Anti-Michael addition" of Grignard reagents to sulfonylacetylenes: Synthesis of alkynes
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In this work, the addition of Grignard reagents to arylsulfonylacetylenes, which undergoes an "anti-Michael addition", resulting in their alkynylation under very mild conditions is described. The simplicity of the experimental procedure and the functional
- Esteban, Francisco,Boughani, Lazhar,García Ruano, José L.,Fraile, Alberto,Alemán, José
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p. 3901 - 3908
(2017/07/11)
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- Catalytic metathesis of conjugated diynes
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The tungsten benzylidyne complex [PhC≡W{OSi(OtBu)3} 3] efficiently catalyzes the metathesis of conjugated diynes and ring-closing diyne metathesis (see scheme). Although this reaction implies C-C single-bond activation, 13C labeling studies reveal that it proceeds by classical alkylidyne group exchange and involves cleavage and formation of carbon-carbon triple bonds. Copyright
- Lysenko, Sergej,Volbeda, Jeroen,Jones, Peter G.,Tamm, Matthias
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p. 6757 - 6761
(2012/08/13)
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- One-pot synthesis and functionalization of polyynes via alkylidene carbenoids
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A one-pot, two-step method for the synthesis of diynes and triynes is reported. The reaction of a dibromoolefinic precursor with BuLi effects a Fritsch-Buttenberg-Wiechell rearrangement and generates a lithium acetylide intermediate, which is then trapped
- Luu, Thanh,Morisaki, Yasuhiro,Tykwinski, Rik R.
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p. 1158 - 1162
(2008/12/22)
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- One-pot formation and derivatization of di- and triynes based on the Fritsch-Buttenberg-Wiechell rearrangement
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(Chemical Equation Presented) A divergent, one-pot synthesis of functionalized polyynes has been developed. Beginning with the appropriately substituted dibromoolefinic precursor, a carbenoid Fritsch-Buttenberg-Wiechell (FBW) rearrangement is used to gene
- Luu, Thanh,Morisaki, Yasuhiro,Cunningham, Nina,Tykwinski, Rik R.
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p. 9622 - 9629
(2008/03/15)
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- Highly efficient and selective synthesis of conjugated triynes and higher oligoynes of biological and materials chemical interest via palladium-catalyzed alkynyl-alkenyl coupling
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(Diagram presented) Iteration of a Pd-catalyzed reaction of alkynyl- and oligoynylzincs with (E)-ICH=CHCl followed by metalation-termination with electrophiles(E) has provided a linear route to conjugated tri- and tetraynes, and Pd-catalyzed monoalkynylation of 1,1-dibromoenynes accompanied by dehydrobromination has provided a convergent route to conjugated tri-, tetra-, and pentaynes. Both display unprecedented high efficiency and selectivity.
- Metay, Estelle,Hu, Qian,Negishi, Ei-Ichi
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p. 5773 - 5776
(2007/10/03)
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- Polyynes, IV. Synthesis of Unsymmetrically Substituted Diacetylenes via 1,1,2-Trichloro-1-alken-3-ynes
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Phenylacetylene (1a) and 1-hexyne (1b) react with bromo(ethyl)magnesium and trichloroacetaldehyde to the corresponding acetylenic carbinols 2.Successive treatment of 2 with phosphorus pentachloride and triethylamine furnishes via the 1,1,1,2-tetrachloro-3
- Himbert, Gerhard,Umbach, Hermann,Barz, Michael
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p. 661 - 667
(2007/10/02)
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- REGIOSELECTIVE ADDITION OF HYDRAZINES TO ALLENYLACETYLENES - CONVENIENT ROUTE TO 3(5)-METHYL-5(3)-SUBSTITUTED PYRAZOLES
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It is shown that hydrazine hydrate, methylhydrazine, and phenylhydrazine add smoothly and regioselectively to allenylacetylenes to give 3(5)-methyl-5(3)-substituted pyrazoles.In addition to the principal process, isomerization of allenylacetylenes to methyldiacetylenes, and the degree of which depends on the structure of the substrate, is observed in the reaction of methylhydrazine in an aqueous alcohol medium.
- Khrimyan, A. P.,Karapetyan, A. V.,Badanyan, Sh. O.
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p. 189 - 196
(2007/10/02)
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