- Towards Isocoumarin-Fused Enediyne Systems through the Electrophilic Cyclization of Methyl o-(Buta-1,3-diynyl)benzoates
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The synthesis of enediynes fused to an isocoumarin core was achieved through the electrophilic cyclization of o-(buta-1,3-diynyl)benzoates as a key step, followed by the Sonogashira coupling of the resulting 3-ethynyl-4-iodoisocoumarins with acetylenes. T
- Danilkina, Natalia A.,Gurskaya, Larisa Y.,Vasilyev, Aleksander V.,Balova, Irina A.
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- A new type of carborane-based electron-accepting material
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In this study, a new type of carborane-based electron acceptor was prepared by the direct attachment of an ethynyl group to the carboranyl carbon atom. Analyses of photophysical and electrochemical and DFT calculations suggested that the direct attachment of the ethynl group significantly affects the electrochemical properties of these o-carborane systems. This journal is
- Lee, Sunhee,Shin, Jisu,Ko, Doo-Hyun,Han, Won-Sik
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supporting information
p. 12741 - 12744
(2020/11/02)
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- Iron(II)-Based Metalloradical Activation: Switch from Traditional Click Chemistry to Denitrogenative Annulation
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A unique concept for the intermolecular denitrogenative annulation of 1,2,3,4-tetrazoles and alkynes was discovered by using a catalytic amount of Fe(TPP)Cl and Zn dust. The reaction precludes the traditional, more favored click reaction between an organic azide and alkynes, and instead proceeds by an unprecedented metalloradical activation. The method is anticipated to advance access to the construction of important basic nitrogen heterocycles, which will in turn enable discoveries of new drug candidates.
- Roy, Satyajit,Khatua, Hillol,Das, Sandip Kumar,Chattopadhyay, Buddhadeb
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p. 11439 - 11443
(2019/07/17)
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- Transition-Metal-Free Synthesis of Borylated Thiophenes via Formal Thioboration
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A simple, regiocontrolled, and transition-metal-free approach to access exclusively 3-borylated thiophene derivatives is reported. The commercially available B-chlorocatecholborane reagent (ClBcat) acts as a carbophilic Lewis acid to activate the alkyne i
- Bel Abed, Hassen,Blum, Suzanne A.
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supporting information
p. 6673 - 6677
(2018/10/24)
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- A Traceless Tether Strategy for Achieving Formal Intermolecular Hexadehydro-Diels-Alder Reactions
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A synthetic strategy formally equivalent to an intermolecular hexadehydro-Diels-Alder (HDDA) reaction is described. Sulfur-based linkers were designed and constructed by joining terminal alkynes or diynes using alkyne thiolate chemistry. The resulting tetraynes and triynes successfully underwent HDDA cyclization and benzyne trapping. Linker removal by reductive desulfurization was uneventful. The strategy was also found suitable for the tetradehydro-Diels-Alder (TDDA) reaction.
- Smela, Merrick Pierson,Hoye, Thomas R.
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p. 5502 - 5505
(2018/09/12)
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- Cyclobutene vs 1,3-Diene Formation in the Gold-Catalyzed Reaction of Alkynes with Alkenes: The Complete Mechanistic Picture
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The intermolecular gold(I)-catalyzed reaction between arylalkynes and alkenes leads to cyclobutenes by a [2 + 2] cycloaddition, which takes place stepwise, first by formation of cyclopropyl gold(I) carbenes, followed by a ring expansion. However, 1,3-butadienes are also formed in the case of ortho-substituted arylalkynes by a metathesis-type process. The corresponding reaction of alkenes with aryl-1,3-butadiynes, ethynylogous to arylalkynes, leads exclusively to cyclobutenes. A comprehensive mechanism for the gold(I)-catalyzed reaction of alkynes with alkenes is proposed on the basis of density functional theory calculations, which shows that the two pathways leading to cyclobutenes or dienes are very close in energy. The key intermediates are cyclopropyl gold(I) carbenes, which have been independently generated by retro-Buchner reaction from stereodefined 1a,7b-dihydro-1H-cyclopropa[a]naphthalenes.
- De Orbe, M. Elena,Amenós, Laura,Kirillova, Mariia S.,Wang, Yahui,López-Carrillo, Verónica,Maseras, Feliu,Echavarren, Antonio M.
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supporting information
p. 10302 - 10311
(2017/08/09)
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- Copper(I)-Catalyzed Enantioselective Addition of Enynes to Ketones
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A copper(I)-catalyzed enantioselective addition of enynes to ketones was developed. The method allows facile construction of enantiomerically enriched tertiary alcohols using skipped enynes as stable hydrocarbon pronucleophiles. The combination of a soft
- Wei, Xiao-Feng,Xie, Xiao-Wei,Shimizu, Yohei,Kanai, Motomu
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p. 4647 - 4650
(2017/04/10)
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- Copper Catalysis for Selective Heterocoupling of Terminal Alkynes
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A Cu-catalyzed selective aerobic heterocoupling of terminal alkynes is disclosed, which enables the synthesis of a broad range of unsymmetrical 1,3-diynes in good to excellent yields. The results disprove the long-held belief that homocouplings are exclusively favored in the Glaser-Hay reaction.
- Su, Lebin,Dong, Jianyu,Liu, Long,Sun, Mengli,Qiu, Renhua,Zhou, Yongbo,Yin, Shuang-Feng
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supporting information
p. 12348 - 12351
(2016/10/07)
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- Syntheses of trifluoroethylated unsymmetrical 1,3-diynes by using 1,1-dichloro-2,2,2-trifluoroethane
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Copper-mediated reaction of terminal 1,3-diynes with 1,1-dichloro-2,2,2-trifluoroethane (CF3CHCl2) using ethanolamine as ligand gave trifluoroethylated unsymmetrical 1,3-diynes in moderate to good yields. The reaction were carried out under mild conditions, and were easy to operate. Aryl groups with weak electron-withdrawing group or electron-donating group, and alkyl substitutents at terminal 1,3-diynes were tolerated. Synthesis of a trifluoroethylated conjugated triyne by using this method was demonstrated. Further transformation of the trifluoroethylated unsymmetrical 1,3-diyne to provide trifluoroethyl-substituted 1,2,3-triazole and isoxazole as application examples were successfully realized.
- Zheng, Jian,Chen, Qing-Yun,Sun, Ke,Huang, Yangen,Guo, Yong
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p. 5757 - 5760
(2016/12/06)
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- Copper mediated oxidative coupling between terminal alkynes and CuCN
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A direct oxidative cross coupling between terminal alkynes and CuCN to form 1-cyanoalkynes was reported. FeCl3 was employed as the sole additive. The reaction could be carried out under mild conditions, with moderate to good yields.
- Li, Yihang,Shi, Dunfa,Zhu, Pengqi,Jin, Hongxing,Li, Shuo,Mao, Feng,Shi, Wei
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supporting information
p. 390 - 392
(2015/04/27)
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- Highly enantioselective copper(i)-catalyzed conjugate addition of 1,3-diynes to α,β-unsaturated trifluoromethyl ketones
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The conjugate diynylation of α,β-unsaturated trifluoromethyl ketones is carried out in the presence of a low catalytic load (2.5 mol%) of a copper(i)-MeOBIPHEP complex, triethylamine and a terminal 1,3-diyne. Pre-metalation of the terminal 1,3-diyne with stoichiometric or higher amounts of dialkylzinc reagent is not required. The corresponding internal diynes bearing a propargylic stereogenic center are obtained with good yields and excellent enantioselectivities. This journal is
- Sanz-Marco, Amparo,Blay, Gonzalo,Mu?oz, M. Carmen,Pedro, José R.
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supporting information
p. 8958 - 8961
(2015/05/27)
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- Scope and limitations of the intermolecular furan-yne cyclization
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Different types of alkynes were reacted with 2,5-disubstituted furans in order to evaluate the scope of the intermolecular furan-yne reaction. With ethynyl aryl ethers as starting materials, 2-phenoxy phenols were accessible in moderate to good yields. A different reaction mode was observed for alkynes bearing electron-withdrawing substituents. For these starting materials a cis-selective hydroarylation took place in an anti-Markovnikov fashion in excellent yields. 1,2-Diynes turned out to be suitable starting materials as well. Due to the second alkynyl moiety, after an initial phenol synthesis, a subsequent hydro-alkoxylation by the newly formed phenolic oxygen gives access to benzofurans in a tandem process.
- Zeiler, Anna,Ziegler, Michael J.,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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p. 1507 - 1514
(2015/08/04)
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- AgOTf-catalyzed electrophilic cyclization of triynols with NXS: Rapid synthesis of densely trisubstituted naphthalenes and quinolines
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A silver triflate-catalyzed electrophilic cyclization reaction of acyclic triynols with NXS (X=I, Br) under mild conditions is reported. Three reactive functional groups, such as a carbonyl group, an alkyne group, and a halogen, could be selectively installed at the C1, C2, and C3 positions to obtain the naphthalene and quinoline products, respectively. The obtained densely trisubstituted products could be further transformed into more complex aromatic products by manipulating the alkynyl moiety and the other two functional groups as synthons. Copyright
- Chen, Zhiyuan,Jia, Xuegong,Ye, Changqing,Qiu, Guanyinsheng,Wu, Jie
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supporting information
p. 126 - 130
(2014/01/06)
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- Electrophilic cyclization of aryldiacetylenes in the synthesis of functionalized enediynes fused to a heterocyclic core
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An efficient strategy for the synthesis of asymmetrically substituted enediynes fused to benzothiophene, benzofuran, and indole was developed. The proposed approach is based on the electrophilic cyclization of diacetylenes and Sonogashira coupling. Thus, iodocyclization of readily available ortho-functionalized (buta-1,3-diynyl)arenes was used as a direct way for the synthesis of 2-ethynyl-3-iodoheteroindenes. These substrates and their modified derivatives were easily converted by Sonogashira coupling with acetylenes to a variety of asymmetrically substituted acyclic enediynes fused to heterocycles. The tolerance of the developed methodology to a variety of functional groups is a great advantage in the synthesis of macrocyclic enediyne systems fused to a heterocyclic core. Synthesis of indole-fused 12-membered macrocyclic dienediyne was achieved using ring-closing metathesis as a key step.
- Danilkina,Kulyashova,Khlebnikov,Br?se,Balova
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p. 9018 - 9045
(2015/01/08)
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- Copper-catalyzed three-component synthesis of 3-Aminopyrazoles and 4-iminopyrimidines via β-alkynyl-N-sulfonyl ketenimine intermediates
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3-Aminopyrazoles and 4-iminopyrimidines were efficiently prepared via copper-catalyzed three-component reactions of butadiynes, sulfonylazides, and hydrazides or imidamides. The reactions were regioselectively approached via the formation of a β-alkynyl-N-sulfonyl ketenimine intermediate which represented a new and effective 1,3-dielectrophilic equivalent in organic synthesis.
- Xing, Yanpeng,Cheng, Binyu,Wang, Jing,Lu, Ping,Wang, Yanguang
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supporting information
p. 4814 - 4817
(2015/04/27)
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- Air-stable (phenylbuta-1,3-diynyl)palladium(II) complexes: Highly active initiators for living polymerization of isocyanides
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A family of air-stable (phenylbuta-1,3-diynyl)palladium(II) complexes were designed and prepared in a facile synthetic procedure. Their structures were characterized by 1H and 13C NMR, MS, and X-ray analysis. These Pd complexes were
- Xue, Ya-Xin,Zhu, Yuan-Yuan,Gao, Long-Mei,He, Xiao-Yue,Liu, Na,Zhang, Wu-Yi,Yin, Jun,Ding, Yunsheng,Zhou, Hongping,Wu, Zong-Quan
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p. 4706 - 4713
(2014/04/17)
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- Nucleophilic conjugate 1,3-addition of phosphines to oligoynoates
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Herein we have elucidated unusual and unique nucleophilic conjugate 1,3-addition reactions of surveyed oligoynoates toward phosphines through spectroscopic and single crystal X-ray diffraction analyses of three-component reaction products of oligoynoates, phosphines and aldehydes. This journal is the Partner Organisations 2014.
- Deng, Jie-Cheng,Kuo, Chih-Wei,Chuang, Shih-Ching
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p. 10580 - 10583
(2014/09/30)
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- Synthesis of fluoro- and perfluoroalkyl arenes via palladium-catalyzed [4 + 2] benzannulation reaction
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An efficient entry into densely substituted fluorinated and perfluoroalkylated benzene derivatives via chemo- and regioselective Pd-catalyzed [4 + 2] cross-benzannulation is presented. The synthetic utility of these products for the synthesis of various aromatic and heteroaromatic compounds is also demonstrated. This strategy offers a viable and quite general alternative to existing fluorination and perfluoroalkylation methods for securing these valuable molecules.
- Zatolochnaya, Olga V.,Gevorgyan, Vladimir
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supporting information
p. 2562 - 2565
(2013/06/26)
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- Zinc-mediated enantioselective addition of terminal 1,3-diynes to N-arylimines of trifluoropyruvates
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A facile and effective enantioselective addition of terminal 1,3-diynes to acyclic α-CF3 ketimine esters has been developed by using zinc/Binol complexes. The reaction works well with a variety of aromatic-, aliphatic- and silyl-substituted diynes, providing the desired products in up to 97% yield and 97% enantiomeric excess.
- Zhang, Fa-Guang,Ma, Hai,Zheng, Yan,Ma, Jun-An
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scheme or table
p. 7663 - 7669
(2012/09/05)
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- From highly enantioselective catalytic reaction of 1,3-diynes with aldehydes to facile asymmetric synthesis of polycyclic compounds
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(S)-1,1′-Binaphth-2-ol (BINOL) in combination with ZnEt2, Ti(OiPr)4, and biscyclohexylamine was found to catalyze the highly enantioselective (83-95% ee) addition of various 1,3-diynes to aldehydes of diverse structures. This method provides a convenient pathway to generate a number of optically active dienediynes as the acyclic precursors to polycyclic compounds. The chiral dienediynes undergo highly chemoselective Pauson-Khand (PK) cycloaddition in benzaldehyde by using [Rh(cod)Cl]2 as the catalyst in the presence of rac-BINAP. High diastereoselectivity (up to >20:1) has also been achieved with the chiral dienediyne substrates containing a bulky substituent adjacent to the chiral center. In the presence of the Grubbs II catalyst, ring-closing enyne metathesis of the PK cycloaddition products led to the formation of the desired 5,5,7- and 5,5,8-fused tricyclic compounds. Further highly diastereoselective Diels-Alder reaction of a 5,5,7-tricyclic compound with maleic anhydride produced a 5,5,7,6-polycyclic product. The asymmetric synthesis of polycyclic compounds from optically active dienediynes has established a novel and efficient synthetic route to the structural framework of many biologically significant molecules.
- Turlington, Mark,Du, Yuhao,Ostrum, Samuel G.,Santosh, Vishaka,Wren, Kathryne,Lin, Tony,Sabat, Michal,Pu, Lin
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supporting information; experimental part
p. 11780 - 11794
(2011/09/16)
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- Synthesis of (Z)-1-organylthiobut-1-en-3-ynes: Hydrothiolation of symmetrical and unsymmetrical buta-1,3-diynes
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Hcny BRAdrothiolation of l-organcny BRAlbuta-l,3-dicny BRAnes and 1,4-diorgancny BRAlbuta-l,3-dicny BRAnes with the sodium organcny BRAlthiolate anions, which were generated in situ bcny BRA reacting diphencny BRAl and dibutcny BRAl disulfide with NaBHsu
- Dabdoub, Miguel J.,Dabdoub, Vania B.,Lenard?o, Eder J.,Hurtado, Gabriela R.,Barbosa, Sandro L.,Guerrero Jr., Palimécio G.,Nazário, Carlos E. D.,Viana, Luiz H.,Santana, Amanda S.,Baroni, Adriano C. M.
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experimental part
p. 986 - 990
(2009/10/23)
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- Synthesis and solid-state polymerization of triyne and enediyne derivatives with similar π-conjugated structures
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Three diacetylene monomer model compounds with similar π-conjugation systems, 10-phenyl-5,7,9-decatriynyl W-phenylcarbamate (1), (E)-10-phenyldec-9- en-5,7-diynyl /V-phenylcarbamate (2), and (E)-10-phenyldec-5-en-7,9-diynyl N-phenylcarbamate (3), were synthesized and their properties and solid-state polymerization were investigated. Based on the absorption spectra of the monomers, it was found that the conjugation effect of a double bond was different from that of a triple bond in solution. Monomers 1,2, and 3 gave one, two, and five crystal forms, respectively, of which 1 and one of the crystal forms of 2 (2a) could be polymerized in the solid state. The conversions after y-ray irradiation (1 MGy dose) were 53% and 20%, respectively. The longest-wavelength absorption maxima of the polymers prepared from 1 and 2a were 645 and 655 nm, respectively. The polymerizable crystals 1 and 2a were found to have layered monomer structures with spacing of 3.1-3.6 nm. Based on solid-state 13CNMR spectra, the polymerization sites of 1 were determined to be the 1,4- and 3,6-positions with respect to the phenyl ring, and that of 2a was determined to be the 3,6-position with respect to the phenyl ring.
- Mizukoshi, Kana,Okada, Shuji,Kimura, Tatsumi,Shimada, Satoru,Matsuda, Hiro
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experimental part
p. 1028 - 1037
(2009/04/13)
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- Enantioselective epoxidation of conjugated cis-enynes by chiral dioxirane
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(Chemical Equation Presented) This paper describes a highly chemo- and enantioselective epoxidation of conjugated cis-enynes using readily available glucose-derived ketone 2 as catalyst and Oxone as oxidant to form cis-propargyl epoxides in high ee's. The
- Burke, Christopher P.,Shi, Yian
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p. 4093 - 4097
(2008/02/04)
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- Electrophilic cyclization of (Z)-selenoenynes: Synthesis and reactivity of 3-iodoselenophenes
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(Chemical Equation Presented) We present here our results of the electrophilic cyclization reaction of (Z)-selenoenynes with different electrophiles such as I2, ICl, PhSeBr, and PhSeCl. The cyclization reaction proceeded cleanly under mild reac
- Alves, Diego,Luchese, Cristiane,Nogueira, Cristina W.,Zeni, Gilson
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p. 6726 - 6734
(2008/02/11)
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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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- Are terminal aryl butadiynes stable? Synthesis and X-ray crystal structures of a series of aryl- and heteroaryl-butadiynes (Ar-C≡C-C≡C-H)
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The synthesis and isolation are reported of a range of terminal aryl- and heteroaryl-butadiynes (ArC≡C-C≡CH) 4a-h from 2-methyl-6-(aryl/ heteroaryl)hexa-3,5-diyn-2-ol precursors. The stability of 4a-h in solution is concentration dependent: many of the de
- West, Kara,Wang, Changsheng,Batsanov, Andrei S.,Bryce, Martin R.
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p. 8541 - 8544
(2007/10/03)
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- One-pot conversion of activated alcohols into 1,1-dibromoalkenes and terminal alkynes using tandem oxidation processes with manganese dioxide
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Approaches to the preparation of C1-homologated dibromoalkenes and terminal alkynes from activated alcohols using one-pot tandem oxidation processes (TOPs) with manganese dioxide are outlined. The conversion of alcohols into dibromoalkenes is described using dibromomethyltriphenylphosphonium bromide and the formation of terminal alkynes was achieved via a sequential one-pot, two-step process utilising the Bestmann-Ohira reagent.
- Quesada, Ernesto,Raw, Steven A.,Reid, Mark,Roman, Estelle,Taylor, Richard J.K.
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p. 6673 - 6680
(2007/10/03)
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- One-pot conversion of activated alcohols into terminal alkynes using manganese dioxide in combination with the Bestmann-Ohira reagent
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The direct conversion of activated primary alcohols into terminal alkynes through a sequential one-pot, two-step process involving oxidation with manganese dioxide and then treatment with the Bestmann-Ohira reagent is described. This transformation proceeds efficiently (59-99% yield) under mild reaction conditions with a range of benzylic, heterocyclic and propargylic alcohols. A tandem variant is also described, which is successful only with highly activated substrates.
- Quesada, Ernesto,Taylor, Richard J.K.
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p. 6473 - 6476
(2007/10/03)
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- A modular approach to α-arylated carbonyl compounds via indium tris(bistriflylamide)-catalyzed regioselective addition of β-ketoesters to 1,3-diynes
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A modular synthesis of α-arylated carbonyl compounds has been achieved by the combination of an indium-catalyzed regioselective addition of β-keto esters to conjugated diynes and a palladium-catalyzed benzannulation reaction. Indium tris(bistriflylamide),
- Nakamura, Masaharu,Endo, Kohei,Nakamura, Eiichi
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p. 1681 - 1686
(2007/10/03)
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- Contingency and Serendipity in the Reactions of Fischer Carbene Complexes with Conjugated Triynes
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The first examples of reactions of Fischer carbene complexes with triynes are reported. The regioselectivity of the reaction of the two different alkyne functions in the symmetrical triyne depends on the nature of the substituent of the triyne. Bis-silyl-substituted triynes react at the central alkyne unit, whereas bis-aryl- and bis-alkyl-substituted triynes react at the end alkyne unit. The reaction of a Fischer carbene complex with a phenyl substituent also reacts with a bis-silyl-substituted triyne at the central alkyne unit but gives a furan product rather than the normal phenol product. It was also demonstrated that all three of the alkyne units in conjugated triynes could react in turn with a Fischer carbene complex to give access to trisquinones. Copyright
- Jiang, May Xiao-Wu,Rawat, Manish,Wulff, William D.
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p. 5970 - 5971
(2007/10/03)
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- 3,3,3-Trichloropropyl-1-triphenylphosphorane: A reagent for the synthesis of (Z)-1,3-enynes, (Z,Z)-1-chloro-1,3-dienes, and 1,3-diynes
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,3,3,3-Trichloropropyl-1-triphenylphosphonium chloride is conveniently prepared from 2-chloroethanol, triphenylphosphine, and trichloroacetic acid. Deprotonation of this reagent generates 3,3,3-trichloropropyl-1-triphenylphosphorane, which reacts with aldehydes to give trichloromethylated (Z)-olefins, which are useful for the synthesis of (Z)-1,3-enynes, (Z,Z)-1-chloro-1,3-dienes, and 1,3-diynes in high yields and stereospecificities. Copyright
- Karatholuvhu, Maheswaran S.,Fuchs, Philip L.
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p. 14314 - 14315
(2007/10/03)
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- Simplified synthesis of 1,1′[14C]-methylene-di (2-naphthol). A radiochemical and kinetic approach
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The synthesis of the 1,1′[14C]-methylene-di-(2-naphthol) 2, as the radiolabeled probe of a possible interaction between the β-amyloid fibrils and the di-naphthol mojety in the Alzheimer's disease, is reported. Very simple radiochemical procedure, starting from [ 14C]paraformaldehyde, produced 8.66 MBq of compound 2 at the specific radioactivity of 1.22 TBq/mol. A mechanistic and kinetic approach allowed the comprehension of the right experimental conditions. The stability of compound 2 in acetonitrile solution was investigated, denoting a significative decomposition process through the transient formation of the 1,2-naphthyne intermediate. Copyright
- Angelini, Giancarlo,Ursini, Ornella,Minetti, Patrizia,Celona, Diana,De Angelis, Francesco
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p. 543 - 556
(2007/10/03)
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- Synthesis of (Z)-1-phenylseleno-1,4-diorganyl-1-buten-3-ynes: Hydroselenation of symmetrical and unsymmetrical 1,4-diorganyl-1,3-butadiynes
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The hydroselenation of 1-organyl-1,3-butadiynes and 1,4-diorganyl-1,3-butadiynes with the sodium phenylselenolate anion, which was generated in situ by reacting diphenyl diselenide with NaBH4 in aqueous ethanol, results in the regio-, stereo- and chemoselective formation the 1-phenylseleno-4-organyl-1-buten-3-ynes and 1-phenylseleno-1,4-diorganyl-1-buten-3-ynes of Z configuration respectively. The lack of selectivity with the 2-hydroxy-2-methyl-3,5-dodecadiyne was observed and the obtained product structures were studied in detail.
- Dabdoub, Miguel J.,Baroni, Adriano C.M.,Lenard?o, Eder J.,Gianeti, Thiago R.,Hurtado, Gabriela R.
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p. 4271 - 4276
(2007/10/03)
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- Ultraviolet photochemistry of diacetylene: Reactions with benzene and toluene
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The reactions of metastable diacetylene with benzene and toluene are explored using a molecular beam pump-probe time-of-flight mass spectrometer. Diacetylene is laser-excited to the 210610 band of the 1Δu←X1Σ+g transition, whereupon rapid intersystem crossing occurs to the lowest triplet states. The triplet state diacetylene then reacts with either benzene or toluene as the gas mixture traverses a short reaction tube (approximately 20 μs). The reactions are quenched as the gas mixture expands into the ion source region of a time-of-flight mass spectrometer where the primary photoproducts are detected using vacuum ultraviolet (VUV) photoionization or resonant two-photon ionization (R2PI). The major products from the reaction of diacetylene and benzene have molecular formulas C8H6 and C10H6, and are identified as phenylacetylene and phenyldiacetylene using R2PI spectroscopy. The major products from metastable diacetylene's reaction with toluene are C9H8 and C11H8. The C9H8 product is confirmed as a mixture of o-, m-, and p-ethynyltoluene, with the ortho product dominating. Mechanisms for the formation of the above products are proposed based on deuterium substitution studies of the reactions. The potential importance of these reactions is discussed as they relate to hydrocarbon growth in sooting flames.
- Robinson, Allison G.,Winter, Paul R.,Ramos, Christopher,Zwier, Timothy S.
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p. 10312 - 10320
(2007/10/03)
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- Flash Vacuum Pyrolysis of Stabilised Phosphorous Ylides. Part 4. Stepwise Construction of Terminal 1,3-Diynes, Conjugated Diacetylenic Esters and a Triacetylenic Ester
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Thirteen examples of stabilised alkynol ylides 6 have been prepared and are found, upon flash vacuum pyrolysis (FVP) at 500 deg C, to undergo extrusion of Ph3PO to give the diacetylenic esters 7 in moderate yield.At 750 deg C the same ylides afforded terminal 1,3-diynes 8 although often in poor yield.For R = 2-MeSC6H4 both 7 and 8 undergo secondary loss of Me* and cyclisation to give 2-alkynylbenzothiophene derivatives 9 and 10 in low yield.The first example of an alkadiynol ylide 11 has been prepared and is converted by FVP at 500 deg C into the triacetylenic ester 12.
- Aitken, R. Alan,Seth, Shirley
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p. 2461 - 2466
(2007/10/02)
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- On the Regio- and Stereoselectivity of Nucleophilic Thiol Additions to Polyines
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Nucleophilic thiophenol additions to α,ω-diphenyl polyines Ph-(CC)n-Ph (n = 2-4) (1-3) take a regio- and stereoselective course.The welldefined, crystalline addition products bind the phenylthio group in terminal position of the aliphatic chain, the re
- Zschunke, A.,Muegge, C.,Hintzsche E.,Schroth, W.
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p. 141 - 146
(2007/10/02)
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- Reactions of Ethynylcarbenes Related to Solid-State Polymerization of 1-Phenyl-1,3-butadiyne
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1,8-Diphenyl-1,8-bis(diazo)-octa-4-ene-2,6-diyne was prepared and photolyzed to give 1-phenyl-1,3-butadiyne in high yield.Ethynylphenylcarbene and β-phenyllethynylcarbene generated by photolysis in MTHF at 6 K are in equilibrium in which the latter predom
- Koga, Noboru,Matsumura, Masahiro,Noro, Masaki,Iwamura, Hiizu
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p. 1357 - 1360
(2007/10/02)
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- Preparation of New Complexing Agents Containing a Highly Conjugated Ethynylated Pyridine Subunit
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Highly conjugated 4-ethynyl derivatives of 2,6-pyridinedicarboxylic acid and 2,6-bispyridine have been prepared using coupling reactions between 4-bromo- and 4-ethylnyl-pyridines and acetylenes in the presence of a small
- Haenninen, Elina,Takalo, Harri,Kankare, Jouko
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p. 614 - 619
(2007/10/02)
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- A study of the reactions of 1,3-diynes with organo-cuprates and -argentates
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1,3-Diynes HCC-CC-R' (1, R'= H or Ph) are converted by cuprates M' (R = alkyl; Y = Cl, Br or R; M'= Li, MgCl or MgBr) into a mixture of C-R'>M' (2) and C-R'>M' (3).When R is n-alkyl, adducts 2 are the major pr
- Kleijn, H.,Tigchelaar, M.,Meijer, J.,Vermeer, P.
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p. 337 - 341
(2007/10/02)
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