52835-06-0Relevant academic research and scientific papers
Stereoselective Chromium-Catalyzed Semi-Hydrogenation of Alkynes
Gregori, Bernhard J.,Nowakowski, Michal,Schoch, Anke,P?llath, Simon,Zweck, Josef,Bauer, Matthias,Jacobi von Wangelin, Axel
, p. 5359 - 5363 (2020/09/03)
Chromium complexes have found very little applications as hydrogenation catalysts. Here, we report a Cr-catalyzed semi-hydrogenation of internal alkynes to the corresponding Z-alkenes with good stereocontrol (up to 99/1 for dialkyl alkynes). The catalyst comprises the commercial reagents chromium(III) acetylacetonate, Cr(acac)3, and diisobutylaluminium hydride, DIBAL?H, in THF. The semi-hydrogenation operates at mild conditions (1-5 bar H2, 30 °C).
Stereoselective Alkyne Hydrogenation by using a Simple Iron Catalyst
Gregori, Bernhard J.,Schwarzhuber, Felix,P?llath, Simon,Zweck, Josef,Fritsch, Lorena,Schoch, Roland,Bauer, Matthias,Jacobi von Wangelin, Axel
, p. 3864 - 3870 (2019/07/31)
The stereoselective hydrogenation of alkynes constitutes one of the key approaches for the construction of stereodefined alkenes. The majority of conventional methods utilize noble and toxic metal catalysts. This study concerns a simple catalyst comprised of the commercial chemicals iron(II) acetylacetonate and diisobutylaluminum hydride, which enables the Z-selective semihydrogenation of alkynes under near ambient conditions (1–3 bar H2, 30 °C, 5 mol % [Fe]). Neither an elaborate catalyst preparation nor addition of ligands is required. Mechanistic studies (kinetic poisoning, X-ray absorption spectroscopy, TEM) strongly indicate the operation of small iron clusters and particle catalysts.
Selective partial hydrogenation of alkynes to (Z)-alkenes with ionic liquid-doped nickel nanocatalysts at near ambient conditions
Konnerth, Hannelore,Prechtl, Martin H. G.
supporting information, p. 9129 - 9132 (2016/07/22)
A selective hydrogenation method for forming (Z)-alkenes from alkynes has been developed using a catalyst system of cheap Ni-NPs in a nitrile functionalised imidazolium based ionic liquid (IL) operating under very mild reaction conditions of 30-50 °C and 1-4 bar H2 pressure.
Highly active and selective semihydrogenation of alkynes with the palladium nanoparticles-tetrabutylammonium borohydride catalyst system
Hori, Junichi,Murata, Kunihiko,Sugai, Toshiki,Shinohara, Hisanori,Noyori, Ryoji,Arai, Noriyoshi,Kurono, Nobuhito,Ohkuma, Takeshi
supporting information; experimental part, p. 3143 - 3149 (2010/04/06)
Palladium nanoparticles are prepared from palladium(II) acetate and 2 equivalents of potassium tert-butoxide in the presence of 4-octyne. The palladium nanoparticles-tetrabutylammonium borohydride system shows excellent catalytic activity and selectivity in the semihydrogenation of alkynes to the [(Z)-]alkenes. The hydrogenation of 4-octyne is conducted with the catalyst system at a substrate-to-palladium molar ratio of 10,000-200,000 under 8 atm of hydrogen to give (Z)-4-octene in > 99% yield. Isomerization and over-reduction of the Z-alkene are very slow even after consumption of the alkyne.
Platinum-catalyzed nucleophilic addition of vinylsilanes at the β-position
Miura, Katsukiyo,Inoue, Gen,Sasagawa, Hisashi,Kinoshita, Hidenori,Ichikawa, Junji,Hosomi, Akira
supporting information; experimental part, p. 5066 - 5069 (2009/12/28)
In the presence of catalytic amounts of PtCl2 and metal Iodides, β-substituted vlnylsllanes reacted with aldehydes at the β-position to give allyl silyl ethers. The Pt-catalyzed addition to aromatic aldehydes proceeded efficiently in the presence of Lil. The combined use of PtCl 2 and Mnl2 was found to be effective In addition to aliphatic aldehydes.
Facile hydroboration of (Z)-1-trimethylsilyl-1-alkenes with dichloroborane-dioxane complex: An easy access to gem-dimetalloalkanes containing boron and silicon
Bhat, Narayan G.,Villanueva, Mary A.
, p. 1298 - 1300 (2007/10/03)
(Z)-1-trimethylsilyl-1-alkenes easily prepared by the hydroboration of the corresponding 1-trimethylsilyl-1-alkynes followed by protonolysis with acetic acid, readily react with dichloroborane-dioxane complex in dichloromethane for 6 h. The resulting solution is then treated with 1,3-propane diol in dichloromethane at 0 °C for half an hour to provide the corresponding gem-dimetalloalkanes containing boron and silicon. These α- trimethylsilylalkylboronate esters are purified by vacuum distillation in high yields (72-84%) and the structures of these novel intermediates are further confirmed by selective oxidation with alkaline hydrogen peroxide to provide the corresponding alcohols containing α-trimethylsilyl group in 78-88% isolated yields.
Synthesis of (E)-alkenes via hydroindation of C{triple bond, long}C in InCl3-NaBH4 system
Wang, Chunyan,Yan, Lei,Zheng, Zhiguo,Yang, Deyu,Pan, Yuanjiang
, p. 7712 - 7717 (2007/10/03)
In InCl3-NaBH4-MeCN system, terminal aryl alkynes could couple with aryl iodides and bromides to give disubstituted alkenes via hydroindation of C{triple bond, long}C. In the similar way, (E)-alkenylsilanes were synthesized via reduction of alkynylsilanes in tetrahydrofuran (THF) in high yields. The processes showed high regio- and stereoselectivity.
A facile stereoselective synthesis of (E)-α-silylvinylstannanes via hydromagnesiation of alkynylsilanes
Cai, Mingzhong,Hao, Wenyan,Zhao, Hong,Xia, Jun
, p. 3593 - 3597 (2007/10/03)
(E)-α-Silylvinylstannanes have been synthesized by the hydromagnesiation reaction of alkynylsilanes, followed by the reaction with trialkylstannyl chlorides. (E)-α-Silylvinylstannanes can undergo the cross-coupling reaction with aryl iodides in the presence of a catalytic amounts of Pd(PPh3)4 and CuI to afford (Z)-1,2-disubstituted vinylsilanes in good yields.
A simple synthesis of B-2-(1-trimethylsilyl-1-alkyl)-1,3,2-dioxaborinanes. Isolation and selective oxidation to 1-trimethylsilyl-1-alkanols
Bhat, Narayan G.,Garza, Amanda
, p. 6833 - 6835 (2007/10/03)
(Z)-1-Trimethylsilyl-1-alkenes easily prepared by the hydroboration of the corresponding 1-trimethylsilyl-1-alkynes followed by protonolysis with acetic acid, readily react with dibromoborane-methyl sulfide complex in dichloromethane for 6 h. The resulting solution is then treated with 1, 3-propane diol in a 1:1 mixture of dichloromethane and n-pentane at 0°C for half an hour to provide the corresponding gem-dimetalloalkanes containing boron and silicon. These alpha-trimethylsilylalkylboronate esters are purified by vacuum distillation in high yields (72-84%) and the structures of these novel intermediates are further confirmed by selective oxidation with alkaline hydrogen peroxide to provide the corresponding alcohols containing trimethylsilyl group.
