Meihua Xie

Homolysis of the Ln–N (Ln = Yb, Eu) bond. Synthesis, structural characterization and catalytic activity of ytterbium(II) and europium(II) complexes with methoxyethyl functionalized indenyl ligands

The interaction of methoxyethyl functionalized indene compounds (C(9)H(6)-1-R-3-CH(2)CH(2)OMe, R =t-BuNHSiMe(2)(1), Me(3)Si (2), H (3)) with [(Me(3)Si)(2)N](3)Ln(mu-Cl)Li(THF)(3)(Ln=Yb (4), Eu (5)) produced a series of new ytterbium(II) and europium(II) complexes via tandem silylamine elimination/homolysis of the Ln-N (Ln=Yb, Eu) bond. Treatment of the lanthanide(III) amides [(Me(3)Si)(2)N](3)Ln(mu-Cl)Li(THF)(3)(Ln=Yb (4), Eu (5) with 2 equiv. of, 1,2 and 3, respectively, produced, after workup, the ytterbium(II) complexes [eta5:eta1-Me(2)Si(MeOCH(2)CH(2)C(9)H(5))(NHBu-t)](2)Yb(II) (6), (eta5:eta1-MeOCH(2)CH(2)C(9)H(5)SiMe(3))(2)Yb(II) (7), (eta5:eta1-MeOCH(2)CH(2)C(9)H(6))(2)Yb(II)(8) and the corresponding europium(II) complexes [eta5:eta1-Me(2)Si(MeOCH(2)CH(2)C(9)H(5))(NHBu-t)](2)Eu(II)(9), (eta5:eta1-MeOCH(2)CH(2)C(9)H(5)SiMe(3))(2)Eu(II)(10) and (eta5:eta1-MeOCH(2)CH(2)C(9)H(6))(2)Eu(II)(11) in moderate to good yield. In contrast, interaction of the corresponding indene compounds 1, 2 or 3 with the lanthanide amides [(Me(3)Si)(2)N](3)Ln (Ln = Yb, Eu) was not observed, while addition of 0.5 equiv. of anhydrous LiCl to the corresponding reaction mixture produced, after workup, the corresponding ytterbium(II) or europium(II) complexes. All the new compounds were fully characterized by spectroscopic and elemental analyses. The structures of complexes, and were determined by single-crystal X-ray analyses. The catalytic activity of all the ytterbium(II) and europium(II) complexes on MMA polymerization was examined. It was found that all the ytterbium(II) and europium(II) complexes can function as single-component MMA polymerization catalysts. The temperature, solvent and ligand effects on the catalytic activity were studied.

Construction of Substituted Benzenes via Pd-Catalyzed Cross-Coupling/Cyclization Reaction of Vinyl Halides and Terminal Alkynes.

A tandem Sonogashira coupling/cyclization/aromatization sequence of β-halo vinyl sulfones/ketones with terminal alkynes has been developed for the construction of benzene rings. Polysubstituted functionalized benzenes containing a sulfonyl or an acyl group could be obtained in up to 95% yield.

FeCl3 · 6H2O-Catalyzed Bromocyclization to Access Functionalized Dihydropyrans

Abstract The FeCl3 · 6H2O-catalyzed bromocyclization of polysubstituted 2,5-hexadiene-1-ol provides a simple method to synthesize functionalized 2,3,4,6-tetrasubstituted 5,6-dihydro-2H-pyrans.

Stereoselective Synthesis of Allylic Amines by One-Pot Tandem Reaction of Acetylenic Sulfone, Grignard Reagent, and N-Tosylimine

Abstract Polysubstituted allylic amines were regio- and stereoselectively synthesized by a one-pot tandem reaction of Cu(I)-catalyzed carbomagnesiation of acetylenic sulfones and its further reaction with N-tosylimine.

Preparation of selanyl-substituted conjugated enynes by copper-catalysed coupling reaction of (E)-γ-selanyl vinylzirconocene with acetylenic bromide

A stereoselective synthesis of conjugated enynes containing allyl selenide unit is reported. Selanyl-substituted conjugated enynes were obtained by the coupling reaction of (E)-γ-selanyl vinylzirconocene with acetylenic bromide in the presence of CuCl.

Stereoselective synthesis of substituted allyl selenide by the reaction of (E)-3-selanyl vinylzirconocene chloride with aldehydes or acyl chlorides

A regio- and stereoselective synthesis of substituted allyl selenides is described. Hydrozirconation of propargyl selenides and its further reaction with aldehydes or acyl chlorides afford 4-selanyl allyl alcohols or 4-selanyl-2-en-1-one, respectively.