- Direct Access to α,β-Unsaturated Ketones via Rh/MgCl2-Mediated Acylation of Vinylsilanes
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We report herein the facile and practical construction of α,β-unsaturated ketones via rhodium-catalyzed direct acylation of vinylsilanes with readily available and abundant carboxylic acids. This protocol features access to a diverse array of synthetically useful functionalities with moderate to excellent yields. More importantly, the late-stage functionalization of pharmaceuticals was also realized with synthetically useful yield.
- Chen, Zi-Yan,Deng, Xue-Zu,Song, Yang,Xue, Fei,Yamane, Motoki,Yue, Yan-Ni
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p. 12693 - 12704
(2021/09/28)
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- In Situ Generation of Silylzinc by Si?B Bond Activation Enabling Silylzincation and Silaboration of Terminal Alkynes
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A new protocol has been designed for the in situ generation of unstable Si?Zn species through the reaction of dialkylzinc, phosphine, and silylborane (Si?B). Successive reactions with various terminal alkynes using this protocol enabled highly controllable regio-/stereo-/chemoselective silylzincation and silaboration on demand without the need for a transition-metal catalyst.
- Nagashima, Yuki,Yukimori, Daiki,Wang, Chao,Uchiyama, Masanobu
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supporting information
p. 8053 - 8057
(2018/06/04)
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- Additive-modulated switchable reaction pathway in the addition of alkynes with organosilanes catalyzed by supported Pd nanoparticles: Hydrosilylation: versus semihydrogenation
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We herein report supported Pd nanoparticles on N,O-doped hierarchical porous carbon as a single operation catalyst-enabled additive-modulated reaction pathway for alkynes addition with organosilanes between hydrosilyation and semihydrogenation. In the case of alkynes hydrosilylation, a simple iodide ion as an additive has a promotion effect on the activity and regio- and stereoselectivity, where iodide can coordinate with Pd NPs via strong δ donation to increase the electron density of the Pd atom, resulting in an increased ability for the oxidative addition of hydrosilane as the rate-determining step to make the reaction proceed efficiently to afford vinylsilanes in high yields with excellent regio- and stereoselectivity. For the catalytic transfer semihydrogenation of alkynes, water was introduced to mix with organosilane to form a silanol together with the generation of hydrogen atoms on the Pd NPs surface or the liberation of H2 gas as a reducing agent, whereby the quantitative reduction of alkynes was achieved with exclusive selectivity to alkenes. In both cases, the catalyst could be recycled several times without a significant loss in activity or selectivity. A broad range of alkyl and aryl alkynes with various functional groups are compatible with the reaction conditions. The role the additive exerted in each reaction was extensively investigated through control experiments as well as the kinetic isotopic effect along with spectroscopic characterization. In addition, the respective mechanism operating in both reactions was proposed.
- Duan, Yanan,Ji, Guijie,Zhang, Shaochun,Chen, Xiufang,Yang, Yong
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p. 1039 - 1050
(2018/03/05)
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- PALLADIUM-MEDIATED REACTION BETWEEN ARYL IODIDES AND STEREODEFINED 2-ARYLETHENYLDIMETHYLPHENYLSILANES OR 2-ARYLETHYNYLDIMETHYLPHENYLSILANES, IN THE PRESENCE OF A FLUORIDE ION SOURCE
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Stereodefined 2-arylethenyldimethylphenylsilanes, 1, do react with aryl iodides, 6, containing an electron-donating substituent as well as with 2-thienyl iodide, 7, in the presence of a catalytic amount of a palladium complex and a molar excess of a 1 M T
- Rossi, Renzo,Carpita, Adriano,Messeri, Tommaso
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- Synthetic applications of stereodefined 2-substituted 1-silyl-1-stannylethenes: A new synthesis of 5-ethenyl-5'-(1-propynyl)-2,2'-bithiophene, a naturally-occurring phototoxin
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(E)-2-(5-Trimethylstannyl-2-thienyl)ethenyldimethylphenylsilane, (E)-8, which can be stereospecifically prepared from (Z)-1-dimethylphenylsilyl-2-(2-thienyl)-1-trimethylstannyl-ethene, (Z)-6, or from (E)-2-(2-thienyl)ethenyldimethylphenylsilane, (E)-9, se
- Rossi,Carpita,Messeri
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p. 1875 - 1888
(2007/10/02)
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