Cooligomerization of Butadiene with Olefins

Cooligomerization of butadiene with some olefinic compounds has been carried out. Two moles of allene reacted at 120°C with butadiene by the catalysis of Pd(PPh3)2 (maleic anhydride) to give cis- and trans-2-methyl-3-methylene-l,5,7-octatriene (119) in 39% yield (104)  

Linear cooligomerization of butadiene with styrene using ir-allylpalla-dium chloride and BF3 complex of PPh3 as a catalyst at 100°C in nitrobenzene or dichloromethane produced 1 -phenyl-1,4-hexadiene (124) (109)  

These cooligomerization reactions can be explained by the following mechanism. First, insertion of butadiene to palladium hydride gives the methyl-substituted 7r-allylpalladium complex 125. Subsequently, insertion of the olefin to the unsubstituted side of the 7r-allyl system and /3-elimination give the 1,4-hexadiene and palladium hydride  

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