704-43-8Relevant academic research and scientific papers
Design, Synthesis, and Implementation of Sodium Silylsilanolates as Silyl Transfer Reagents
Yamagishi, Hiroki,Saito, Hayate,Shimokawa, Jun,Yorimitsu, Hideki
, p. 10095 - 10103 (2021/08/18)
There is an increasing demand for facile delivery of silyl groups onto organic bioactive molecules. One of the common methods of silylation via a transition-metal-catalyzed coupling reaction employs hydrosilane, disilane, and silylborane as major silicon sources. However, the labile nature of the reagents or harsh reaction conditions sometimes render them inadequate for the purpose. Thus, a more versatile alternative source of silyl groups has been desired. We hereby report a design, synthesis, and implementation of storable sodium silylsilanolates that can be used for the silylation of aryl halides and pseudohalides in the presence of a palladium catalyst. The developed method allows a late-stage functionalization of polyfunctionalized compounds with a variety of silyl groups. Mechanistic studies indicate that (1) a nucleophilic silanolate attacks a palladium center to afford a silylsilanolate-coordinated arylpalladium intermediate and (2) a polymeric cluster of silanolate species assists in the intramolecular migration of silyl groups, which would promote an efficient transmetalation.
Sodium silylsilanolate enables nickel-catalysed silylation of aryl chlorides
Hitoshio, Kenshiro,Yamagishi, Hiroki,Shimokawa, Jun,Yorimitsu, Hideki
supporting information, p. 6867 - 6870 (2021/07/19)
Structurally diverse aryl chlorides were silylated with sodium silylsilanolate reagents in the presence of a Ni(cod)2catalyst complexed with a phosphine ligand; PMe2Ph for electron-rich substrates, and PCy2Ph for electron-deficient ones. The mild reaction conditions allowed the silylation of various aryl chlorides including functionalised drug molecules.
Sterically facilitated meta-lithiation of arenes, containing electron-donating groups
Antonov, Alexander S.,Bardakov, Victor G.,Mulloyarova, Valeriia V.
supporting information, (2019/12/11)
The influence of the bulky trimethylsilyl substituent on the selectivity of metallation of dimethylaniline, anisole and 1-dimethylaminonaphthalene is studied. The neighboring SiMe3 group forces dimethylamino and methoxy groups to occupy a confo
Nickel-Catalyzed Decarbonylation of Acylsilanes
Ito, Yuri,Kodama, Takuya,Nakatani, Syun,Sakurai, Shun,Tobisu, Mamoru
, p. 7588 - 7594 (2020/06/27)
Nickel-catalyzed decarbonylation of acylsilanes is developed. In sharp contrast to cross-coupling reactions of acylsilanes, in which the silyl group serves as a leaving group, the silyl group is retained in the product in this decarbonylation reaction. Although the strong binding of the dissociated CO to the nickel center frequently hinders catalyst turnover in nickel-mediated decarbonylative reactions, this reaction can be catalyzed by nickel complexes bearing a CO ligand.
Direct ortho Arylation of Anisoles via the Formation of Four-Membered Lithiumcycles/Palladacycles
Xiong, Xiaoyu,Zhu, Ranran,Huang, Lin,Chang, Shuqin,Huang, Jianhui
supporting information, p. 2046 - 2050 (2017/09/13)
We report here our latest discovery on the directed lithiation and palladium-catalyzed arylation of anisoles. During this research, the formation of a four-membered lithiumcycle followed by transmetalation to the corresponding palladacycle has been achieved, which is difficult to be obtained from palladium-catalyzed C-H activation processes. This approach has provided an alternative way of introducing functionalities to arenes such as anisoles, thioanisoles, and anilines. This approach also features an excellent monoselectivity compared with reactions under transition-metal-catalyzed conditions.
Deprotonative metalation of functionalized aromatics using mixed lithium-cadmium, lithium-indium, and lithium-zinc species
Snegaroff, Katia,L'Helgoual'ch, Jean-Martial,Bentabed-Ababsa, Ghenia,Nguyen, Tan Tai,Chevallier, Floris,Yonehara, Mitsuhiro,Uchiyama, Masanobu,Derdour, Aicha,Mongin, Florence
experimental part, p. 10280 - 10290 (2010/04/24)
In situ mixtures of CdCl2TMEDA (0.5 equiv; TMEDA = N,N,N',N'-tetramethylethylenediamine) or InCl3 (0.33 equiv) with [Li(tmp)] (tmp = 2,2,6,6-tetramethylpiperidino; 1.5 or 1.3 equiv, respectively) were compared with the previously described mixture of ZnCl2-TMEDA (0.5 equiv) and [Li(tmp)] (1.5 equiv) for their ability to deprotonate anisole, benzothiazole, and pyrimidine. [(tmp)3CdLi] proved to be the best base when used in tetrahydrofuran at room temperature, as demonstrated by subsequent trapping with iodine. The Cd-Li base then proved suitable for the metalation of a large range of aromatics including benzenes bearing reactive functional groups (CONEt2, CO2Me, CN, COPh) or heavy halogens (Br, I), and heterocycles (from the furan, thiophene, pyrrole, oxazole, thiazole, pyridine, and diazine series). Fivemembered heterocycles benefiting from doubly activated positions were similarly dideprotonated at room temperature. The aromatic lithium cadmates thus obtained were involved in palladium-catalyzed cross-coupling reactions or simply quenched with acid chlorides.
Process for performing an in-situ-quench reaction
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Page/Page column 9, (2008/06/13)
Method for carrying out in-situ quench (ISQ) reaction, by producing reactive intermediate in presence of reaction partner comprises (a) supplying a mixture of a precursor(PR), RP and optionally inert diluent to microreactor; (b) mixing in reactor with highly reactive reagent (RR) which converts PR into RI; and (c) isolating final product formed by reaction of RI with RP (optionally after flowing through a residence time unit). A method for carrying out an in-situ quench (ISQ) reaction, by producing a reactive intermediate (RI) in presence of a reaction partner (RP), involves: (a) supplying a mixture of a precursor(PR), RP and optionally an inert diluent to a microreactor; (b) mixing in the reactor with a highly reactive reagent (RR) which converts PR into RI; and (c) isolating the final product formed by the reaction of RI with RP (optionally after flowing through a residence time unit). An independent claim is included for use of a microreactor for carrying out an ISQ reaction, by supplying a mixture of PR, RP and optionally an inert diluent to the microreactor and mixing with RR.
Syndiospecific living propylene polymerization catalyzed by titanium complexes having fluorine-containing phenoxy-imine chelate ligands
Mitani, Makoto,Furuyama, Rieko,Mohri, Jun-ichi,Saito, Junji,Ishii, Seiichi,Terao, Hiroshi,Nakano, Takashi,Tanaka, Hidetsugu,Fujita, Terunori
, p. 4293 - 4305 (2007/10/03)
The propylene polymerization behavior of a series of Ti complexes featuring fluorine-containing phenoxy-imine chelate ligands is reported. The Ti complexes combined with methylalumoxane (MAO) can be catalysts for living and, at the same time, stereospecific polymerization of propylene at room temperature or above. DFT calculations suggest that the attractive interaction between a fluorine ortho to the imine nitrogen and a β-hydrogen of a growing polymer chain is responsible for the achievement of room-temperature living propylene polymerization. Although the Ti complexes possess C2 symmetry, they are capable of producing highly syndiotactic polypropylenes. 13C NMR is used to demonstrate that the syndiotacticity is governed by a chain-end control mechanism and that the polymerization is initiated exclusively via 1,2-insertion followed by 2,1-insertion as the principal mode of polymerization. 13C NMR spectroscopy also elucidated that the polypropylenes produced with the Ti complexes possess regio-block structures. Substitutions on the phenoxy-imine ligands have profound effects on catalytic behavior of the Ti complexes. The steric bulk of the substituent ortho to the phenoxy oxygen plays a decisive role in achieving high syndioselectivity for the chain-end controlled polymerization. Over a temperature range of 0-50 °C, Ti complex having a trimethylsilyl group ortho to the phenoxy oxygen forms highly syndiotactic, nearly monodisperse polypropylenes (94-90% rr) with extremely high peak melting temperatures (Tm = 156- 149 °C). The polymerization behavior of the Ti complexes can be explained well by the recently proposed site-inversion mechanism for the formation of syndiotactic polypropylene by a Ti complex having a pair of fluorine-containing phenoxy-imine ligands.
Fluorine- and trimethylsilyl-containing phenoxy-imine Ti complex for highly syndiotactic living polypropylenes with extremely high melting temperatures
Mitani, Makoto,Furuyama, Rieko,Mohri, Jun-ichi,Saito, Junji,Ishii, Seiichi,Terao, Hiroshi,Kashiwa, Norio,Fujita, Terunori
, p. 7888 - 7889 (2007/10/03)
A fluorine- and trimethylsilyl-containing phenoxy-imine titanium complex was synthesized and the structure was determined by an X-ray analysis. The complex on activation with MAO initiates highly controlled syndiospecific living propylene polymerization to form extremely high Tm syndiotactic polypropylenes (Mw/Mn = 1.05-1.08, Tm = 156-152 °C) at 0 or 25 °C. Moreover, at 50 °C, the complex afforded monodisperse syndiotactic polypropylene with very high Tm's of 149, 150 °C. In contrast, complexes having a t-Bu group instead of the silyl group provided lower tacticity polymers with much lower Tm's. In addition, we revealed the substituent effect that plays a key role for the highly controlled syndiospecific polymerization displayed by the catalyst. Copyright
