536-74-3Relevant articles and documents
Oxophosphonium-Alkyne Cycloaddition Reactions: Reversible Formation of 1,2-Oxaphosphetes and Six-membered Phosphorus Heterocycles
L?we, Pawel,Feldt, Milica,Wünsche, Marius A.,Wilm, Lukas F.B.,Dielmann, Fabian
, p. 9818 - 9826 (2020)
While the metathesis reaction between alkynes and carbonyl compounds is an important tool in organic synthesis, the reactivity of alkynes with isoelectronic main-group R2E≠O compounds is unexplored. Herein, we show that oxophosphonium ions, which are the
Nickel-Catalyzed Annulation of Aliphatic Amides with Alkynyla silanes: An Expeditious Approach to Five-Membered Lactams
Gao, Fei,Lin, Cong,Lin, Jingyi,Shen, Liang,Teng, Qiuxun,Xu, Yiqing
, p. 889 - 894 (2020)
An expeditious approach for the synthesis of diverse five-membered lactams through nickel-catalyzed annulation of the C(sp 3)-H bonds of aliphatic amides with alkynylsilanes assisted by an 8-Aminoquinolinyl directing group is reported, delivering the corresponding lactam derivatives in moderate to high yields. It is worth noting that alkynylsilanes are employed for the first time as coupling partners in the transition-metal-catalyzed functionalization of C(sp 3)-H bonds of aliphatic amides. Equimolar amounts of alkynylsilanes and aliphatic amides are utilized, which greatly increases the efficiency of this protocol.
Tributylstannyl radical-catalyzed reaction of 1,2,3-selenadiazoles with olefins or dienes
Nishiyama, Yutaka,Hada, Yasunobu,Anjiki, Masahiro,Miyake, Kazuya,Hanita, Sakiko,Sonoda, Noboru
, p. 1520 - 1525 (2002)
It was found that the reaction of 1,2,3-selenadiazoles derived from cyclic ketones with olefins or dienes was markedly promoted by a catalytic amount of tributylstannyl radical, which was generated in situ from tributylstannyl hydride or allyltributylstannane and AIBN, to give the corresponding dihydroselenophenes in moderate to good yields. In contrast, when 1,2,3-selenadiazoles prepared from linear and aromatic ketones were used as substrates, the same reaction did not take place, and alkynes were formed as the sole product.
Alkynylic SRN1 Reaction: Feasible or Not?
Galli, Carlo,Gentili, Patrizia
, p. 2013 - 2014 (1994)
A comparison of the relative propensity of aryl-, vinyl-, and ethynyl-halides towards a SRN1 reaction is made possible by an investigation of some nucleophilic reactions with bromophenylethyne.
Experimental and computational study of the ultraviolet photolysis of vinylacetylene. Part II
Stearns, Jaime A.,Zwier, Timothy S.,Kraka, Elfriede,Cremer, Dieter
, p. 5317 - 5327 (2006)
The ultraviolet photochemistry of vinylacetylene (C4H 4) was studied under temperature and pressure conditions similar to Titan's atmosphere by exciting the molecule in a constrained expansion that opens into the ion source region of a time-of-flight mass spectrometer. The primary dissociation products detected by vacuum-ultraviolet ionization were found to be C4H3 and C4H2, in a ratio of 3-10: 1. Subsequent reaction of the C4H3 radicals with the parent C4H4 produced two major secondary products: C8H6 and C6H4. The former was spectroscopically identified as phenylacetylene, confirming that photochemical reactions of C4H4 can produce aromatic molecules. The primary dissociation reaction was also studied computationally. The results were consistent with the experimental findings for C 4H2 and C4H3. However, the major product is C2H2, which is undetected by 118 nm photoionization in the present experiment but should account for roughly two-thirds of the products. Simulations were also performed to confirm that the present experiment accurately represents the 220 nm photochemistry of vinylacetylene at the temperature and pressure of Titan's atmosphere, with a product yield of C2H2: C4H2: C 4H3 of 66: 7: 27. Accounting for the wavelength dependent solar flux on Titan, the estimated absorption cross section of vinylacetylene in the ultraviolet, and the slightly wavelength dependent product distribution, the overall product yield predicted by the simulations for ultraviolet photolysis of vinylacetylene on Titan is C2H2: C 4H2: C4H3 = 65: 8: 27. Finally, a simulation was performed under conditions of a shock tube experiment to examine the differences between thermal and photochemical dissociation. The product yield of this simulation was C2H2: C4H 2: C4H3 = 61: 1: 38. the Owner Societies 2006.
Formation of Metal Acetylides via Complexes of Molecular Hydrogen
Field, Leslie D.,George, Adrian V.,Hambley, Trevor W.,Malouf, Elizabeth Y.,Young, David J.
, p. 931 - 933 (1990)
Terminal acetylenes react with to form metal acetylides and diacetylides; the crystal structure of trans-Fe(CCPh)2(dmpe)2 shows that the seven atoms of the C-CC-Fe-CC-C grouping are colinear and
Transition-metal-free chemo- and regioselective vinylation of azaallyls
Li, Minyan,Gutierrez, Osvaldo,Berritt, Simon,Pascual-Escudero, Ana,Ye?l?imen, Ahmet,Yang, Xiaodong,Adrio, Javier,Huang, Georgia,Nakamaru-Ogiso, Eiko,Kozlowski, Marisa C.,Walsh, Patrick J.
, p. 997 - 1004 (2017)
Direct C(sp 3)-C(sp 2) bond formation under transition-metal-free conditions offers an atom-economical, inexpensive and environmentally benign alternative to traditional transition-metal-catalysed cross-coupling reactions. A new chemo- and regioselective coupling protocol between 3-aryl-substituted-1,1-diphenyl-2-azaallyl derivatives and vinyl bromides has been developed. This is the first transition-metal-free cross-coupling of azaallyls with vinyl bromide electrophiles and delivers allylic amines in excellent yields (up to 99%). This relatively simple and mild protocol offers a direct and practical strategy for the synthesis of high-value allylic amine building blocks that does not require the use of transition metals, special initiators or photoredox catalysts. Radical clock experiments, electron paramagnetic resonance studies and density functional theory calculations point to an unprecedented substrate-dependent coupling mechanism. Furthermore, an electron paramagnetic resonance signal was observed when the N-benzyl benzophenone ketimine was subjected to silylamide base, supporting the formation of radical species upon deprotonation. The unique mechanisms outlined herein could pave the way for new approaches to transition-metal-free C-C bond formations.
In Situ Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy to Unravel Sequential Hydrogenation of Phenylacetylene over Platinum Nanoparticles
Wondergem, Caterina S.,Hartman, Thomas,Weckhuysen, Bert M.
, p. 10794 - 10802 (2019)
Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) is quickly developing into a powerful characterization tool in heterogeneous catalysis. In this work, we employ Pt catalysts supported on Au@SiO2 shell-isolated nanoparticles to study hydrogenation reactions. First, we demonstrate the facile preparation of Pt/Au@SiO2 and its characterization by using adsorption of CO as probe molecule. Next, we use the adsorption and hydrogenation of phenylacetylene as a model reaction for the interaction of triple bonds and aromatic rings with catalytic Pt surfaces. We show that the applicability of SHINERS is not limited to inherently gaseous compounds, thereby expanding the applicability of the technique to more complex systems. Furthermore, by using nonparticipating side groups as labels, we observe the sequential hydrogenation of phenylacetylene into styrene and ultimately ethylbenzene upon reaction with H2. Upon the absence of H2, the reverse reaction takes place with those molecules still adsorbed onto the catalyst surface, which allowed a more detailed understanding of the reaction mechanism and the assignment of Raman peaks. This strengthens the position of SHINERS as an easily applicable surface sensitive technique that can be used to study a wide variety of chemical reactions in the field of heterogeneous catalysis.
1-Methoxycarbonylpyrrolizin-3-one and related compounds
Despinoy, Xavier L. M.,McNab, Hamish
, p. 2187 - 2194 (2009)
Flash vacuum pyrolysis (FVP) of dimethyl E- or Z-pyrrol-2-ylbut-2-enedioate 5 at 700 °C gave 1-methoxycarbonylpyrrolizin-3-one 1. The sequence involves E- to Z-isomerisation (if necessary), elimination of methanol and cyclisation; the elimination step is
Conversion of Allyl Alk-2-ynoates to Alk-2-ynoic Acids Using Morpholine and Palladium(0)-Bis(diphenylphosphino)alkane Catalyst; Synthesis of 2,2,3,3-Tetradehydro PGE1
Okamoto, Sentaro,Ono, Naoya,Tani, Kousuke,Yoshida, Yukio,Sato, Fumie
, p. 279 - 280 (1994)
Allyl alk-2-ynoates can be readily converted into alk-2-ynoic acids by the reaction with morpholine in the presence of a palladium-diphenylphosphinopropane catalyst, thus providing the chemical deprotection method of allyl ester of 2,2,3,3-tetradehydro PGE1.
