Zirconium compounds reactions, reagents

The chelate compounds, produced as shown in (2), are not decomposed at once by even (1 1) sulfuric acid and therefore a sensitive test for aluminum has been developed on this basis. (Tervalent chromium salts exhibit an analogous behavior.) The color reactions are selective if the test solution is treated with a shght excess of magnesium carbonate before the reagent is introduced. It is essential that sulfuric acid be used for the acidification if hydrochloric acid is employed the zirconimn compounds formed at the same time remain unchanged. The sulfuric acid probably decomposes the colored zirconium compounds through formation of complex zirconium sulfuric acids. Chrome Fast Pure Blue B is the best reagent because its dye acid can be completely extracted by ether, which is not true of some of the related dyes. 

Similarly, copper and zirconium reagents lead to transmetallation reactions with organopalladium compounds. These reagents are particularly useful to introduce a vinyl group into various substrates and has received applications in steroids [30], prostaglandins (Ref. 31) and natural diterpenes [32, 33] synthesis. 

Organogermanium compounds can be prepared by transmetallation reactions with tin reagents. Examples include Me2PhGeCl (Equation (66)),89 the alkene-functionalized species 26-28, (Equations (67) and (68)),90 and the allenic (Equation (69)) and propargylic (Equation (70)) species 29 and 30.91 A series of aryltrichlorogermanes was prepared from the corresponding tin reagents (Equation (71), Table 9).92 Transmetallation with zirconium species can also be used (Equation (72), Table 10).93... 

Zirconium and hafnium dialkylamides are highly reactive compounds. They undergo (i) protolytic substitution reactions with reagents such as alcohols, cyclopentadiene and bisftrimethylsilyOamine 63 64 (ii) insertion reactions with C02, CS2, COS, nitriles, phenyl isocyanate, methyl isothiocyanate, carbodiimides and dimethyl acetylenedicarboxylate 69-72 and (iii) addition reactions with metal carbonyls.73 These reactions are summarized with reference to Zr(NMe2)4 in Scheme 1. 

Addition of the Grignard reagent to the carbon-carbon double bond requires severe reaction conditions.508 513 Zirconium-based compounds, in contrast, catalyze carbomagnesation of 1-alkenes to occur selectively under mild conditions. [NiCl2(PPh3)2] is the best catalyst to promote syn addition to disubstituted acetylenes, although usually in low yields 514... 

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