Copper-Mediated Transformation of Organosilanes to Nitriles with DMF and Ammonium Iodide
摘要:
Cyanation of aryl-, diaryldimethyl-, and styrylsilanes was developed for the first time under copper-mediated oxidative conditions using ammonium iodide and DMF as the combined source of nitrogen and carbon atom of the introduced cyano unit, respectively. The reaction was observed to proceed in a two-step process: initial conversion of organosilanes to their iodo intermediates and then cyanation. This method has a broad substrate scope with high functional group tolerance.
Xphos ligand and platinum catalysts: A versatile catalyst for the synthesis of functionalized β-(E)-vinylsilanes from terminal alkynes
摘要:
Hydrosilylation of functionalized terminal arylalkynes with a variety of silanes catalyzed by PtCl(2) or PtO(2) in the presence of the air-stable and bulky Xphos ligand was investigated. Regardless of the electronic nature ( electron withdrawing or donating group) and the position (o, m, p) of the substituents on the aromatic ring, a single beta-(E)-styrylsilanes was obtained in good to excellent yields. The regioselectivity of the H-Si bond addition was found to be governed by steric effects induced by the bulky Xphos ligand. A dramatic regioselectivity was also observed when functionalized terminal aliphatic alkynes were employed as a substrate and in these cases regioisomeric beta-(E)-vinylsilanes were generated with excellent selectivity. (c) 2008 Elsevier B. V. All rights reserved.
Rhodium(I) Complexes with Ligands Based on N-Heterocyclic Carbene and Hemilabile Pyridine Donors as Highly <i>E</i> Stereoselective Alkyne Hydrosilylation Catalysts
作者:Judith P. Morales-Cerón、Patricia Lara、Joaquín López-Serrano、Laura L. Santos、Verónica Salazar、Eleuterio Álvarez、Andrés Suárez
DOI:10.1021/acs.organomet.7b00361
日期:2017.7.10
substitution at the 6-position of the pyridine donor serve as efficient E-selective alkyne hydrosilylation catalyst precursors. Particularly, when the steric hindrance of the picolyl fragment is increased, a catalyst precursor exhibiting high catalytic activities (TOF up to 500 h–1 at S/C ratios of 1000) and excellent E selectivities (E/α ratio ≥95/5) in the hydrosilylation of a series of aryl, alkyl, and
包含吡啶供体6-位取代度不同的吡啶甲基-NHC(NHC = N-杂环卡宾)配体的阳离子铑(I)络合物可作为有效的E选择性炔烃氢化硅烷化催化剂前体。特别是,当甲基吡啶基片段的空间位阻增加时,催化剂前体表现出高催化活性(S / C比为1000时,TOF高达500 h –1)和极好的E选择性(E在一系列芳基,烷基和官能化的末端炔烃与碳-和烷氧基硅烷的氢化硅烷化反应中,获得了/α比≥95/ 5)。Rh配合物中的吡啶甲基-NHC配体由于吡啶片段的半不稳定配位作用而在溶液中表现出动态行为。初步的机理研究支持了由Rh配合物和硅烷低浓度生成的Rh甲硅烷基氢化物参与炔烃的氢化硅烷化反应,并与Chalk–Harrod型机理的假设相一致。
Distinct Catalytic Performance of Dirhodium(II) Complexes with <i>ortho</i>-Metalated DPPP in Dehydrosilylation of Styrene Derivatives with Alkoxysilanes
provided a stable and rigid dirhodium(II) complex with ortho-metalated DPPP as the bridging ligand and the phosphonate as the axial ligand in the catalytic system. The structure of the dirhodium(II) complexes was also supported by X-raycrystal diffraction. Further experiments confirmed that the dirhodium(II) complexes may be the active species that catalyze the dehydrosilylation reaction. Control experiments
Dichloro(ethylenediamine)platinum(II), a water-soluble analog of the antitumor cisplatin, as a heterogeneous catalyst for a stereoselective hydrosilylation of alkynes under neat conditions
hydrosilylation of internal and terminal alkynesunder heterogeneous catalysis by dichloro(ethylenediamine)platinum(II) is discussed. This commercially available platinum complex operates under neat conditions at 90 °C, producing exclusively the (trans) Z-isomer with symmetrical internal alkynes, while terminal alkynes produce a mixture of α- and β(E)-hydrosilylated products. No β(Z)-hydrosilylated product was
Totally regioselective hydrosilylation of functionalized terminal arylalkynes was achieved using PtCl(2) associated with the air-stable and bulky Xphos ligand with various silanes. Regardless of the electronic nature of the substituents on the aromatic ring, a single beta-(E)-vinylsilane was obtained in excellent yields. (C) 2008 Elsevier Ltd. All rights reserved.
A Rh(I) complex with an annulated N-heterocyclic carbene ligand for E-selective alkyne hydrosilylation
作者:Akshi Tyagi、Suman Yadav、Prosenjit Daw、Chitrakar Ravi、Jitendra K. Bera
DOI:10.1016/j.poly.2019.04.027
日期:2019.11
A Rh(I) complex supported by a fused pi-conjugated imidazo[1,2-a][1,8]naphthyridine-based N-heterocyclic carbene ligand with a Dipp attachment on the imidazole nitrogen has been synthesized and structurally characterized. The title complex is found to be an excellent catalyst for accessing E-vinylsilanes. The scope of the chemoselective hydrosilylation is examined for a range of terminal alkynes with silanes Et3SiH and (EtO)(3)SiH. (C) 2019 Elsevier Ltd. All rights reserved.