Organometallic dihalides

Reaction of organometallic dihalides with the title dilithio reagent afforded silicon and tin metallaindenes (equation 33)96. 

As previously noted (Introduction) a number of metal-containing polyesters have been synthesized employing organometallic dihalides and salts of dicarboxylic acids. Further the synthesis of phosphorus-containing polyesters and polyamides has also been accomplished (for instance 11-15). Previous attempts by our group to synthesize the analogous phosphorus anhydrides failed. 

Organometallic dihalides are typically more reactive than general organic diacid halides and will undergo certain condensations for which analogous products are not formed through attempted condensation with acid chlorides utilizing mild conditions. For instance a... 

Regioselectivity of C—C double bond formation can also be achieved in the reductiv or oxidative elimination of two functional groups from adjacent carbon atoms. Well estab llshed methods in synthesis include the reductive cleavage of cyclic thionocarbonates derivec from glycols (E.J. Corey, 1968 C W. Hartmann, 1972), the reduction of epoxides with Zn/Nal or of dihalides with metals, organometallic compounds, or Nal/acetone (seep.lS6f), and the oxidative decarboxylation of 1,2-dicarboxylic acids (C.A. Grob, 1958 S. Masamune, 1966 R.A. Sheldon, 1972) or their r-butyl peresters (E.N. Cain, 1969). 

Aryl tellurium trichlorides are easily converted to symmetrical or unsymmetrical diaryl tellurium dihalides via reactions with organometallic compounds (see p. 549). Trimethyl(aryl)silanes transfer only the aryl group to tellurium1. 

Because a number of these organometallic compounds are commercially available, they are convenient starting materials for the preparation of certain aliphatic and aromatic diorgano tellurium dihalides. Tetraorgano tin and lead compounds transfer only two of their four organic groups to tellurium. Experiments with dialkyl-diaryl compounds showed that only the aryl groups are transferred. 

A number of organometallic polymers containing metallocenes and metallocene analogues has been well-known for some time2. Because of the features of high-temperature stability and radiation resistance of the ferrocene nucleus, ferrocene-containing polymers are of special interest. Basically, these polymers may be divided into two classes the metallocene moiety is either located in a pendant group or in a backbone of the polymer chain. The former polymers have been synthesized by vinyl polymerization of vinyl metallocene monomers such as vinylferrocene. The latter polymers have been prepared by polycondensation of l,l -disubstituted metallocenes or metallocene dihalides with a.w-disubstituted monomers, and fell into two main types, (A) and (B). 

Diphenylacetylene has been used as a starting point for the generation of metalloindenes of Si (294), Sn (294), and As (45). Reaction of BuLi-tetramethylethylenediamine (TMED) with diphenylacetylene results in addition metallation to produce a dilithio organometallic that will react with a metal dihalide derivative ... 

The dominant method of synthesis for the dibenz derivatives is the reaction of a dilithio organometallic with a metal dihalide. The dibenz-heterocycles are listed in Table X. 

TT-Allylnickel halides are more stable, and thermal disproportionation is not observed even at higher temperatures. Recently, we found that TT-allylnickel halides can be disproportionated easily by treating them in solution with excess gaseous ammonia (2). Bis(7r-allyl)nickel and ammonia adducts of nickel dihalides are obtained in quantitative yields and can be separated easily. In fact, the disproportionation reaction represents at the moment the easiest way to synthesize bis (7r-allyl) nickel type compounds since as mentioned, all types of 7r-allylnickel halides can be prepared easily. The advantage of the new method lies in the fact that bis (TT-allyl) nickel type compounds can be prepared without prior preparation of organometallic allyl compounds, such as Grignard compounds, which are sometimes diflBcult to prepare. The disproportionation of TT-allylnickel halides has an analog in the chemistry of alkyl-mercuric halides, some of which disproportionate under the influence of ammonia (12). 

The ratio of the two Zr(IV) products that one observes depends on the nature of RX primary alkyl halides highly favor the formation of the Zr alkyl complex, tertiary alkyl and acyl halides almost exclusively form the Zr dihalide complex, while mixtures of the two organometallic complexes are observed for secondary halides. The coordinated phosphine ligands invariably are quaternized to phosphonium salts, but this conversion is slower than the rates of oxidation of Zr. 

Very soon after the reactivity of Cd(CF3)2DME toward main group halides (31) and group 10 dihalides (32) had been established, we set out to determine if the cadmium reagent was effective in trifluoromethylating representative organometallic compounds. One of the first substrates chosen was CpCo(CO)I2, which was selected because the mono-trifluoro-methyl derivative was known, but the disubstituted compound was not. The results of this reaction are (60)... 

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