Metal groups allylation

In addition, a catalytic version of Tt-allylpalladium chemistry has been devel-oped[6,7]. Formation of the Tr-allylpalladium complexes by the oxidative addition of various allylic compounds to Pd(0) and subsequent reaction of the complex with soft carbon nucleophiles are the basis of catalytic allylation. After the reaction, Pd(0) is reformed, and undergoes oxidative addition to the allylic compounds again, making the reaction catalytic.-In addition to the soft carbon nucleophiles, hard carbon nucleophiles of organometallic compounds of main group metals are allylated with 7r-allylpalladium complexes. The reaction proceeds via transmetallation. These catalytic reactions are treated in this chapter. 

Many methods have been reported for the addition of allylic groups, including allyltrialkyltin compounds" (in the presence of BF3-etherate), as well as other allylic metal compounds." Allylic alcohols and homo allylic alcohols add to aldehydes in the presence of Sn(OT02 " For allylic halides, both activated... 

Some transition metal ir-allyl compounds are not catalysts for polymerization. For example, Zr (allyl) 4 will not polymerize methyl methacrylate. Spectroscopic and other studies have shown that this allyl compound, unlike those of chromium, react with the carbonyl group of the monomer giving compounds of the type... 

One possible mechanism is electrophilic attack of the complexed carbene carbon atom at the terminal carbon of the diene. The resulting zwitterionic intermediate can now eliminate the metallic group (CO)5M directly, or, alternatively, the metallic group can migrate to yield a new, more stable zwitterion (stabilization of the allyl cation by the heteroatom X). 

Note that in a compound such as allyllithium, where a tr bond connects the carbon to the metal, the allyl group is referred to as monohapto or rjx. 

Members of a Japanese group (101, 102), using polybutadiene as their base polymer, were able to metalate the allylic position of the polybutadiene chain. The allylic anion was then allowed to react with additional monomer to produce a grafted polybutadiene copolymer, Eqs. (33) and (34). 

Aromatic compounds are reduced over the six platinum metal group catalysts at widely different rates, as expected, but additionally the products of reduction frequently vary with the metal used. Many of these results may be correlated in terms of two parameters not obviously connected to aromatic properties the relative tendencies of these catalysts to promote double bond migration in olefins and to promote hydro-genolysis of vinylic and allylic functions. 

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