Jiayun Li

Asymmetric zinc-catalyzed hydrosilylation of ketones and the effect of carboxylate on the enantioselectivity.

Several chiral ligands containing (R,R)-diaminocyclohexane moieties and pyrrole, furan, or benzene have been synthesized. These ligands were tested in enantioselective zinc-catalyzed hydrosilylation reactions; excellent enantioselectivities were obtained when the ligands containing (R,R)-diaminocyclohexane moieties and furan rings were used. For comparison, zinc chloride combined with different potassium carboxylate salts and ligands were also tested for catalytic hydrosilylation reactions.

Use of functionalized PEG with 4-aminobenzoic acid stabilized platinum nanoparticles as an efficient catalyst for the hydrosilylation of alkenes

A catalyst containing functionalized polyethylene glycol with 4-aminobenzoic acid (PEG-AMB) stabilized platinum nanoparticles has been synthesized and characterized, and its application in the hydrosilylation of alkenes investigated. It is shown that the functionalized PEG-stabilized Pt nanoparticles form a very efficient catalyst for the hydrosilylation of alkenes. The Pt nanoparticles can be fully immobilized in the PEG-AMB and recycled at least nine times without any obvious loss of catalytic activity.

Rapid Selective Defunctionalization of the Carbonyl Group of α,β-Unsaturated Ketones with Trialkoxylsilane/ZnX2

Abstract Reduction of the carbonyl group of ketones to a methylene unit is widely applied in organic syntheses. In this article, we report that trialkoxylsilane/Zn-based catalyst systems may be applied in the reduction of the carbonyl groups of α,β-unsaturated ketones to methylene units under very mild conditions. In comparison with other Zn-based catalysts, excellent rates and high conversions of α,β-unsaturated ketones to methylene units are obtained using trialkoxylsilane/ZnI2 or ZnCl2. And the same time, the hydrosilylation reaction product could only be detected when using CuI, CuCl, or FeCl3. No reaction could be conducted by using trialkoxylsilane/CoCl2 or NiCl2, in comparison with Zn-based catalysts. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Rh(PPh3)3Cl/Tetrakis(Dialkylamino)Phosphonium Salts as Thermoregulated and Recyclable Catalytic System for Hydrosilylation Reaction

Abstract Eleven tetrakis(dialkylamino)phosphonium salts have been prepared and were used as “soft” catalyst supports for the hydrosilylation reaction of styrene with triethoxysilane catalyzed by Rh(PPh3)3Cl. Among the Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts tested, the best catalytic activity and selectivity in favor of the β-adduct were obtained when {[(C4H9)2N]3[(C8H17)2N]P}PF6 was used as the support, and Rh(PPh3)3Cl/ {[(C4H9)2N]3[(C8H17)2N]P}PF6 catalyst system can be reused more than 10 times without noticeable loss of catalytic activity and selectivity. GRAPHICAL ABSTRACT

The catalytic activity of alkali metal alkoxides and titanium alkoxides in the hydrosilylation of unfunctionalized olefins

Abstract The catalytic activities of titanium alkoxides and alkali metal alkoxides for hydrosilylation of unfunctionalized olefins have been studied. Titanium(IV) alkoxides showed excellent catalytic activity, while alkali metal alkoxides have low catalytic activity for the hydrosilylation of olefins. However, by using titanocene dichloride as an additive, alkali metal alkoxides showed also excellent catalytic property for hydrosilylation. In comparison with titanium alkoxides, no α-adduct was obtained by using alkali metal alkoxides/Cp2TiCl2 as catalysts. GRAPHICAL ABSTRACT

Titanium-catalyzed hydrosilylation of olefins: A comparison study on Cp2TiCl2/Sm and Cp2TiCl2/LiAlH4 catalyst system

Abstract Hydrosilylation of olefins catalyzed by Cp2TiCl2/Sm (Cp = cyclopentadienyl) under solvent free conditions have been investigated. By using Cp2TiCl2/Sm as catalyst system, β-adducts and hydrogenation products were detected. Hydrosilylation of olefins catalyzed by Cp2TiCl2/LiAlH4 under room temperature has also been studied. The influence of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) on Cp2TiCl2/Sm and Cp2TiCl2/LiAlH4, respectively, indicated that hydrosilylation of olefins catalyzed with Cp2TiCl2/Sm went through a free radical reaction pathway while a coordination mechanism was applied for Cp2TiCl2/LiAlH4 catalyst system. GRAPHICAL ABSTRACT

N-heterocyclic carbene platinum complexes functionalized with a polyether chain and silyl group: Synthesis and application as a catalyst for hydrosilylation

GRAPHICAL ABSTRACT ABSTRACT The synthesis and characterization of new N-heterocyclic carbene platinum(II) complexes functionalized with a polyether chain and silyl group are described. In addition, their application towards the catalytic hydrosilylation of unsaturated carbon–carbon bonds, including alkenes, alkynes, vinyl ether, and unsaturated esters, is reported. These new complexes exhibit both excellent catalytic activity and selectivity for hydrosilylation. The catalytic system can be recycled >27 times.

Hydrosilylation of Ketones Catalyzed with Mg-Al-O-t-Bu Hydrotalcite

Abstract In this article, a simple and efficient procedure of hydrosilylation of ketones catalyzed with Mg-Al-O-t-Bu hydrotalcite was described. Hydrosilylation of ketones with triethoxysilane was carried out smoothly at room temperature in the presence of Mg-Al-O-t-Bu hydrotalcite without solvent, and the conversions of ketones were more than 90%. The recyclability of Mg-Al-O-t-Bu hydrotalcite was also tested.