Zirconiums organo

A comparison has been made" of various monoterpenoid rearrangements cataiysed by either zirconium phosphates or by zirconium organo-substituted phosphonates, and acid-catalysed rearrangements of a-trans- and /3-cis-3,4-epoxycaranes have been described." It has been observed" that on exposure to Li (OBu )3AlH, perhydro-naphthalene-l,4-diol monosulfonate ester (269) rearranges to the 11-oxatricyclo-[5.3.1.0.2,6]undecane derivative (270) (see Scheme 88). 

D. J. Cardin, M. F. Lappert, and C. L. Raston, Chemistry of Organo-Zirconium and -Hafnium Compounds, Hasted Press, Division of John Wiley Sons,... 

LiNa Geng et al. realized similar experiments for the adsorption of trypsin [141] and hemoglobin [142] on y-zirconium phosphate (y-ZrP) and organo y-ZrP intercalated with butylammonium (BA) and tetrabutylammonium (TBA). Hb adsorbed in the galleries of BA-y-ZrP and TBA-y-ZrP mainly by hydrophobic... 

Neoalkoxy zirconates also provide novel opportunities for the adhesion of fluorinated polymers to metal substrates because the introduction of a zirconate at the interface results in a metal oxygen zirconium VI organo fluoride. 

It has recently been established that carbozirconation with organylzirconocene derivatives evidently requires dipolar (and mostly bimetallic) activation and/or small-ring zirconacycles, especially three-membered ones, that can undergo cyclic carbozirconation (Generalization 6 ) [149]. One of the recent examples has been shown to involve both bimetallic and cyclic organo-zirconium species [150], These reactions can be either stoichiometric or catalytic in Zr. 

The different reactivities of the carbon—boron and carbon—zirconium bonds toward electrophiles are a consequence of the different bond polarities and the different electronegativities of boron and zirconium. Moreover, zirconium is a transition metal, while boron exhibits intriguing transition metal-like chemistry [55], It is thus reasonable to presume that the combined use of boron and zirconium in organic chemistry should be synergistic, affording products and chemistry not attainable with the individual organo-metallics alone. 

Cardin, D.J., Lappert, M.F. and Raston, C.L. (1986) Chemistry of Organo-Zirconium and Organo-Hajhium Compounds, John Wiley Sons, Inc, New York. 

Two recent papers on [(jj-CsHs)M(S2CNMe2)3] (M = Zr or Hf)486 and [(fj-C5H5)2ZrCl(S2CNR2)] (R = Me or Et)487 are mentioned in passing to provide an entry into the current literature on organo-zirconium and -hafnium dithiocarbamato complexes. 

Aluminum hydrides add across carbon-carbon multiple bonds to form organo-alanes381-385 (hydroalanation or hydroalumination), which are usually further reacted with suitable electrophiles. The addition is thermal or may be catalyzed by metals, mainly titanium and zirconium compounds.386,387... 

The coupling agents which have been most extensively used are various organo-silicon compounds, although several other types of compound of quite different chemistry, including zirconium and titanium comlexes [1], have also been used. It is with silane materials that we are concerned here. 

Nagishi, E. and Liu, F., Palladium- or Nickel-catalyzed Cross-coupling with Organo-metals Containing Zinc, Magnesium, Aluminium and Zirconium , in Metal-catalyzed Cross-coupling Reactions, Wiley-VCH, Weinheim, 1998, pp. 1-47. 

Zirconium-aluminum analogs of the Tebbe reagent have been reported to react with carbonyl compounds slowly, in low yield or not at all. However, zirconium aUcylidenes which are stabilized by a phosphorus rather than an aluminum ligand do transfer their alkylidene moiety to carbonyl. These results provide some of the few examples of long chain alkylidene transfer to ca nyl from an organo-metallic reagent (equation 31). 

Titanium and zirconium tetrabenzyl and the mixed metal—benzyl halides are soluble in hydrocarbon solvents and will polymerize ethylene and a-olefins, the latter to stereo-specific polymers [64], The structures of the true initiators are not known but they are unlikely to be the simple organo-metal compounds. Catalysts of higher activity are obtained when they are used in combination with aluminium alkyls. It is of interest to note that titanium tetra(dimethyl amide) reacts with acrylonitrile to form an active species, which then forms high molecular weight polymer by coordination polymerization [65]. 

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