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Pd-catalyzed Negishi reactions of Zr and Hf complexes bearing η5-4-bromo-2-methylindenyl and η5-2-bromoindenyl ligands with MeZnCl and various aryl- and heteroarylzinc reagents (RZnCl) give in high yields the respective complexes bearing η5-4-R-2-methylindenyl and η5-2-R-indenyl ligands, respectively.

A new procedure was developed for the synthesis of a broad range of ansa-zirconocenes containing bis(2-methyl-4-arylindenyl)dimethylsilane ligands. The method is based on the palladium-catalyzed reaction of halogen-substituted bis(indenyl)dimethylsilanes with various organozinc compounds. The aryl-substituted bridging ligands thus prepared serve as the starting compounds for the synthesis of ansa-zirconocenes, which can be used as components of promising catalysts for propylene polymerization.

Substituted 4-/7-halo-1H-indenes and 5-methyl-3-bromo-4-/6H-cyclopenta[b]thiophenes were shown to be convenient starting materials for Suzuki−Miyaura, Negishi, and Murahashi protocols to give the corresponding aryl-subsituted indenes and cyclopenta[b]thiophenes of importance for further synthesis of ansa-metallocenes. Alternatively, (2-methyl-1H-inden-4-yl)boronic acid and (1-methoxy-2-methyl-2,3-dihydro-1H-inden-4-yl)boronic acid as well as the respective organozinc and -magnesium reagents can be used for synthesizing aryl-subsituted indenes via the Pd-catalyzed reactions with aryl halides. These synthetic methods were shown to have a very broad scope to afford libraries of aryl-substituted indenes. Finally, synthesis and structure characterization of several representative chiral ansa-zirconocenes, potentially useful as components of highly active and stereoselective olefin polymerization catalysts, have been performed.

Constrained geometry complexes (CGCs) of titanium (IV) and zirconium (IV) containing isomeric cyclopentadienyls fused to thiophene fragment, i.e., 4,5-dimethylcyclopenta[ b ]thienyl and 5,6-dimethylcyclopenta[ b ]thienyl, have been prepared and unambiguously characterized. The molecular structure of the titanium complex [η 5 -(5,6-dimethylcyclopenta[ b ]thienyl)SiMe 2 (N t Bu)-η 1 ]TiCl 2 was established by X-ray crystal structure analysis. Preliminary studies showed that the studied CGCs/MAO are active olefin polymerization catalysts.

A series of 2-R2P-substituted indenes, where R2P = Ph2P, Cy2P, iPr2P, and tBu(H)P, were obtained via Pd-catalyzed reactions of 2-bromo-1H-indene (or 1H-inden-2-yl trifluoromethane sulfonate) with R2PH/Et3N. Analogous indenes bearing Me2P, tBu(Cl)P, and tBu2P substituents at position 2 were obtained through the reaction of 1H-inden-2-ylphosphonous dichloride with MeLi, tBuMgCl, and tBuMgCl/tBuLi−CuCN, respectively. Diethyl 1H-inden-2-ylphosphonate, prepared via the Ni-catalyzed Arbuzov reaction of 2-bromo-1H-indene with P(OEt)3, was found to be a convenient starting material for the synthesis of 2-H2P-substituted indene. 1H-Inden-2-yl(phenyl)phosphine, prepared via the Pd-catalyzed arylation of 2-H2P-substituted indene by PhI, turned out to react with 2-bromo-1H-indene in the presence of Pd(PPh3)4 and Et3N to form di(1H-inden-2-yl)(phenyl)phosphine in almost quantitative yield. Analogously, di(1H-inden-2-yl)(tert-butyl)phosphine was prepared via catalytic reaction of tBuPH2 with 2 equiv of 2-bromo-1H-inden...

The following cyclopentadienes (Cp‘H) with fused thiophene and benzothiophene fragments were synthesized: 4,5-dimethyl-6H-cyclopenta[b]thiophene (2), 5,6-dimethyl-4H-cyclopenta[b]thiophene (4), 1,...

Substituted 4-/7-halo-1H-indenes and 5-methyl-3-bromo-4-/6H-cyclopenta[b]thiophenes were shown to be convenient starting materials for Suzuki−Miyaura, Negishi, and Murahashi protocols to give the corresponding aryl-subsituted indenes and cyclopenta[b]thiophenes of importance for further synthesis of ansa-metallocenes. Alternatively, (2-methyl-1H-inden-4-yl)boronic acid and (1-methoxy-2-methyl-2,3-dihydro-1H-inden-4-yl)boronic acid as well as the respective organozinc and -magnesium reagents can be used for synthesizing aryl-subsituted indenes via the Pd-catalyzed reactions with aryl halides. These synthetic methods were shown to have a very broad scope to afford libraries of aryl-substituted indenes. Finally, synthesis and structure characterization of several representative chiral ansa-zirconocenes, potentially useful as components of highly active and stereoselective olefin polymerization catalysts, have been performed.

By treatment of Cp*ZrCl3 with the lithium salt of cyclopenta[b]pyridine (LiCpPy) in toluene, the unsymmetrical complex Cp*(η5-CpPy)ZrCl2 was prepared in 32% yield. On the evidence of X-ray crystal structure analysis, the bifunctional CpPy ligand coordinates Zr in an η5-manner rather than via nitrogen. Cyclopenta[b]pyridine turned out to react with Zr(NMe2)4 in toluene to form mono-cyclopentadienyl complex (η5-CpPy)Zr(NMe2)3(Me2NH) in 70% yield. The polymerization of ethylene and the copolymerization of ethylene with 1-hexene or propene catalyzed by Cp*(η5-CpPy)ZrCl2 activated with MAO was studied in detail.