Insertion reactions of ethylene into

C02 insertions into the Cu(I)-H and Cu(I)-CH3 bonds (equations 4 and 5) were theoretically investigated and compared with the similar insertion reactions of ethylene into the Cu(I)-H and Cu(I)-CH3 bonds (eqs 6 and 7)... 

The most generally accepted mechanistic speculations center about a y3-acetoxyalkylpalladium intermediate (VI) formed by an insertion reaction of ethylene into a palladium-oxygen bond (Reaction 3). It is proposed that this intermediate would then decompose via a palladium-assisted hydride transfer to vinyl acetate (Reaction 4) (36). While Reaction 4 would appear more awkward than a simple )3-hydrogen... 

Conversion of 6.3 to 6.4 is a simple insertion reaction of ethylene into the Ti-Et bond. This is followed by successive rapid insertions of ethylene molecules into the Ti-carbon bond to give 6.5. Chain termination with release of the polymer can take place by two different pathways either by /3-elimination or by the reaction of 6.5 with hydrogen. 

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