- Dehydrogenative Coupling of Terminal Alkynes with O/N-Based Monohydrosilanes Catalyzed by Rare-Earth Metal Complexes
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Newly synthesized rare-earth metal alkyl complexes bearing a tripyrrolyl ligand act as excellent precatalysts for the cross-dehydrogenative coupling between various terminal alkynes and O/N-based monohydrosilanes of HSi(OEt)3/HSi(NMe2)3, leading to the formation of a variety of alkoxysilylalkyne and aminosilylalkyne derivatives in good to high yields. The precatalysts LRE(CH2SiMe3)(thf)2 (RE = Y(1a), Er(1b), Yb(1c), L = 2,5-[(2-C4H3N)CPh2]2(C4H2NMe), thf = tetrahydrofuran) were easily prepared in high yields via the reactions of RE(CH2SiMe3)3(thf)2 with the proligand H2L in a single step. Mechanistic studies reveal that treatment of 1 with phenylacetylene could generate the active catalytic species: dinuclear rare-earth metal alkynides (L(thf)n[RE(μ-CCPh)]2L) (RE = Y(5a), n = 1; Yb(5c), n = 0), which could react with HSi(OEt)3 to produce the coupling product 4aa and the dinuclear rare-earth metal hydrides (L (thf)[RE(μ-H)]2L) (RE = Y(6a); Yb(6c)). By contrast, prior treatment of 1c with HSi(OEt)3 proceeds via cleavage of the Si-O bond to produce the dinuclear ytterbium alkoxide (LYb(μ-OEt))2 7c, which is inert in the dehydrogenative coupling reaction. The results of the mechanistic studies are consistent with the observation that the reaction is greatly influenced by the addition sequence of precatalyst/alkynes/silanes.
- Guo, Dianjun,Huang, Zeming,Pan, Mengke,Sheng, Tian,Wang, Shaowu,Zha, Ling,Zhou, Shuangliu,Zhu, Xiancui
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- Reactivity of [TismPriBenz]MgMe towards secondary amines and terminal alkynes: Catalytic dehydrocoupling with hydrosilanes to afford Si–N and Si–C bonds
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The magnesium hydride and methyl compounds, [TismPriBenz]MgX (X = H, Me), react with diphenylamine (Ph2NH)and pyrrolidine (C4H8NH)to afford the amide derivatives, [TismPriBenz]MgNPh2 and [TismPriBenz]MgNC4H8, while reactions with the terminal alkynes, PhC[tbnd]CH and BunC[tbnd]CH, afford the corresponding acetylide derivatives, [TismPriBenz]MgC[tbnd]CPh and [TismPriBenz]MgC[tbnd]CBun. The Mg[sbnd]N bond of [TismPriBenz]MgNR2 may be cleaved by hydrosilanes, such that [TismPriBenz]MgMe is an effective precatalyst for the dehydrocoupling of hydrosilanes and amines. For example, [TismPriBenz]MgMe enables the conversion of a 1:1 mixture of Ph2SiH2 and C4H8NH at room temperature to the silazane, Ph2SiH(NC4H8). [TismPriBenz]MgH and [TismPriBenz]MgMe are also capable of dehydrocoupling PhC[tbnd]CH and PhSiH3 to form PhSiH2C[tbnd]CPh. In addition to dehydrocoupling of terminal alkynes, [TismPriBenz]MgMe is also capable of achieving the isomerization 3-phenyl-1-propyne to phenylallene.
- Rauch, Michael,Roberts, Renee C.,Parkin, Gerard
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p. 271 - 279
(2019/07/02)
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- Sodium triethylborohydride as a catalyst for the dehydrogenative silylation of terminal alkynes with hydrosilanes
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The first example of sodium triethylborohydride-catalyzed C(sp)-H bond silylation is reported. The reaction of aromatic and aliphatic alkynes with aromatic hydrosilanes and hydrosiloxanes proceeded in a highly selective manner to afford dehydrocoupling pr
- Skrodzki, Maciej,Witomska, Samanta,Pawlu?, Piotr
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supporting information
p. 5948 - 5951
(2018/05/14)
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- B(C6F5)3/Amine-Catalyzed C(sp)?H Silylation of Terminal Alkynes with Hydrosilanes: Experimental and Theoretical Studies
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Transition metal catalyzed C?H functionalization of organic compounds has proved to be a useful atom-efficient strategy in organic synthesis. In contrast, main-group-element-based catalytic processes for C?H functionalization have remained underexplored t
- Ma, Yuanhong,Lou, Shao-Jie,Luo, Gen,Luo, Yong,Zhan, Gu,Nishiura, Masayoshi,Luo, Yi,Hou, Zhaomin
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supporting information
p. 15222 - 15226
(2018/10/25)
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- Dehydrogenative coupling between hydrosilanes and alkynes catalyzed by alkoxides, alkylmetals, and metalamides
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The selective dehydrogenative coupling reaction between phenylsilane and ethynylbenzene occurred in the presence of some homogeneous base catalysts such as alkoxides, alkyl compounds, and the amides of alkali metals or barium. The order of the catalytic activities was Ba(OR)2 > LiN(SiMe3)2 ~ n -BuLi > LiOEt. Barium alkoxide showed the highest activity and selectivity for the reaction, and gave the polymer poly[(phenylsilylene)ethynylene-1,3-phenyleneethynylene] in the reaction of phenylsilane with m-diethynylbenzene. The correlation between the catalytic activities and the catalyst basicities was discussed, and a reaction mechanism involving both the metal acetylide and the metal hydride was proposed.
- Ishikawa, Jun-Ichi,Itoh, Masayoshi
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p. 454 - 461
(2007/10/03)
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- Dehydrogenative cross-coupling reactions between phenylsilane and ethynylbenzene in the presence of metal hydrides
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Dehydrogenative cross-coupling reactions occurred between phenylsilane and ethynylbenzene in the presence of the metal hydrides, such as LiAlH4, NaAlH4, LiBH4 and LiAlH(Ot-Bu)3 to produce some ethynyl compounds.
- Ishikawa, Jun-Ichi,Inoue, Kohji,Itoh, Masayoshi
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p. 303 - 311
(2007/10/03)
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- Copper(I) chloride catalyzed cross-dehydrocoupling reactions between silanes and ethynyl compounds. A new method for the copolymerization of silanes and alkynes
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In the presence of an amine, copper(I) chloride is an effective catalyst for the cross-dehydrocoupling of silanes with alkynes.The reactions proceed at useful rates above 100 deg C, but rates drop dramatically on going from 1o to 2o
- Liu, Hua Qin,Harrod, John F.
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p. 1100 - 1105
(2007/10/02)
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