Zirconocene dichloride synthesis

Fluorenyl- /-fluorenyl complexes, with Ti(IV), 4, 406 Fluorenyl hafnocene dichlorides, synthesis, 4, 943 Fluorenyl zirconocene dichlorides, synthesis, 4, 943 Fluorescence resonance energy transfer, in high-throughput catalyst discovery, 1, 358 Fluorescent sensors, Pt acetylenes as, 12, 472... 

Jutzi, R Muller, C. Neumann, B. Stammler, H.-G Dialkylaminoethyl-functionalized msa-zirconocene dichlorides Synthesis, structure, and polymerization properties. J. Organomet. Chem. 2001,625, 180-185. 

A useful synthesis of alkynes and particularly of terminal ( )-enynes results from the insertion of the readily formed ( )-l,2-dichloro-l-lithioethene (68) into organozirconocene chlorides (Scheme 3.17). An intermediate ( )-2-chloroalkenyl zirconium species 69 undergoes anti-elimination of zirconocene dichloride to yield terminal alkynes 70 [38]. 

The results of 1H- and 13C-NMR analysis of the complexes 11-13 are given in Table 8. For comparison, the NMR resonances of the corresponding fragments of the zirconocene dichloride and free diamine used in the synthesis of amido zirconium complexes are also shown. 

Arylations. A rather unusual reaction for the synthesis of triarylmethanes is that which involves benzylic arylation of 4-nitrotoluene and homologs catalyzed by Pd(OAc)2-PhjP in the presence of CS2CO3. One or two aryl groups can be introduced by this method. Arylation of amines by ArX employs the Pd(OAc)2-f-BuONa and a phosphine as catalyst. Pentaarylcyclopentadienes are readily formed in a reaction of metallocenes (nickelocene, titanocene dichloride, zirconocene dichloride) with ArBr in... 

Treatment of zirconocene dichloride, 50, with 2 equiv. of an appropriate alkyllithium or Grignard reagent generates transient zirconocene olefin complexes that upon loss of alkene provide access to zirconocene, 109, and the powerful reduction chemistry of divalent zirconium.48 Owing to the utility of this reagent in organic synthesis and organometallic reactions, the low-temperature alkylation of zirconocene dichloride, 50, with BunLi has been... 

Branch at C-4 - The syntheses of some C-4 branched derivatives of NeuNAc have been achieved from a protected 4-keto analogue, methyl (methyl 5-acetamido-3,5-dideoxy-8,9-6>-isopropylidene-p-D-manno-2,4-nonudiulopyrano-sid)onate. For example conversion of the latter into spiro-epoxide 12 by reaction with zirconocene dichloride-Zn-diiodomethane, then peracid, provided a reactive centre for the addition of carbon centred nucleophiles giving products such as 13. The synthesis of furo[2,3-c]pyran-P-D-thymidine, a potential antiviral agent, is mentioned in Chapter 20. 

Halterman, R. L. Synthesis of chiral titanocene and zirconocene dichlorides. In Metallocenes— Synthesis, Reactivity and Applications, Togni, A., Halterman, R. L., Eds. Wiley-VCH Weinheim, 1998 pp 455-544. 

Alt, H. G. Zenk, R. C2-symmetric bis(fluorenyl) complexes Four complex models as potential catalysts for the isospecific polymerization of propylene. J. Organomet. Chem. 1996, 512, 51-60. Chen, Y.-X. Rausch, M. D. Chien, J. C. W. C2y- and C2-Symmetric an5a-bis(fluorenyl)zirconocene catalysts Synthesis and a-olefin polymerization catalysis. Macromolecules 1995, 28, 5399-5404. Rieger, B. Stereospecific propene polymerization with rac-[l,2-bis(ti -(9-fluorenyl))-l-phenylethane] zirconium dichloride/methylalumoxane. Polym. Bull. (Berlin) 1994,32,41 6. 

Ashe, A. J., Ill Fang, X. Hokky, A. Kampf, J. W. The Cj-symmetric aminoboranediyl-bridged zirconocene dichloride [(r -9-Ci3Hg)-BN( Pr)2(ti-C5H4)]ZrCl2 Its synthesis, structure, and behavior as an olefin polymerization catalyst. Organometallics 2004, 25, 2197-2200. 

For some leading reviews see (a) Resconi, L. Cavallo, L. Fait, A. Piemontesi, F. Selectivity in propene polymerization with metallocene catalysts. Chem. Rev. 2000,100, 1253-1345. (b) Alt, H. G Koppl, A. Effect of the nature of metallocene complexes of Group IV metals on their performance in catalytic ethylene and propylene polymerization. Chem. Rev. 2000, 100, 1205-1221. (c) Halterman, R. L. Synthesis and applications of chiral cyclopentadienyhnetal complexes. Chem. Rev. 1992, 92, 965-994. (d) Halterman, R. L. Synthesis of chiral titanocene and zirconocene dichlorides. In Metallocenes ... 

Rufanov, K. A. Kotov, V. V. Kazeimova, N. B. Lemenovskii, D. A. Avtomonov, E. V. Lorberth, J. Hetero-afua-metaUocenes I. Synthesis of the novel [l]-borylidene-bridged-zirconocene dichloride. J. Organomet. Chem. 1996, 525, 287-289. 

Selective cross-metathesis of allyl-substituted awra-zirconocene dichloride with Pd, Co, and Ni complexes having the acrylate pendant resulted in the synthesis of heterobimetallic complexes Zr/Pd, Zr/Co, and Zr/Ni (Scheme 12.27) [34]. 

Sulfur dichloride was also used in the synthesis of 2,5-bis(trimethylsilyl)-EDOT 52, from which EDOT could be obtained by reaction with fluoride [123], The basis of the route is a zirconocene coupling generating zirconacyclopentadiene 51 from the reaction of two alkynes, linked with a 0(CH2)20 tether, with zirconocene dichloride (bis(cyclopentadienyl)zirconium(IV) dichloride). The zirconacycle reacted with sulfur dichloride generating the thiophene ring of 52 (Scheme 76). 

The synthesis of vinylphosphines has been accomplished using a complimentary process (Scheme 4.314) [416]. The first part of the chemistry consisted of metallocycle formation by treatment of zirconocene dichloride with two equivlents of BuLi followed by the addition of two equivalents of an internal alkyne such as diphenylacety-lene. Treatment of this intermediate with a chlorophosphine should have generated vinylphosphines. However, the authors found that this reaction was low yielding. After some experimentation, they discovered that the conversion of the zirconium metallocycle into a vinylcopper species through the addition of copper chloride followed by addition of the chlorophosphine was an effective route to the formation of the vinylphosphines. 

Four new asymmetric ansa-zirconocene dichlorides, rac-[l-(9-ri -fluorenyl)-2-(2-phenyl-l-ri -indenyl)ethane]zirconium dichloride, rac-[(9-ri -fluorenyl)(5,6-cyclopenta-2-methyl-l-ri -indenyl)dimethylsilane]zirconium dichloride, rac-[(9-ri -fluorenyl)(2-methyl-l-ri -indenyl)dimethylsilane]zirconium dichloride and rac-[(9-r -fluorenyl)(2-phenyl-l-ri -indenyl)dimethylsilane]zirconium dichloride, have been prepared and evaluated as propene polymerisation catalysts. The synthesis of the [2,5-diisopropylcyclohexane-l,4-bis(indenyl)]titanium dichloride and [2,5-diisopropylcyclohexane-l,4-bis(tetrahydroindenyl)]titanium dichloride complexes, shown as 20, and their use as catalysts for the enantioselective pinacol coupling of benzaldehyde have been described. ... 

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