Cyclo-co-oligomerizations

Transition metal catalysts were also found to be useful for the mixed cyclo-co-oligomerization of two 1,3-dienes with an alkene or alkyne. This approach was further extended toward the preparation of heterocyclic systems. " ... 

Cyclo-co-oligomerization of 1,3-Dienes with Oleflns and Alkynes... 

Many transition metals catalyze oligomerization reactions between dienes and olefins or alkynes. Possible reaction products are legion. But it is almost exclusively with zerovalent nickel that cyclic products are formed. Addition of olefins or alkynes to catalysts mentioned in the previous section suppresses the cyclooligomerization and instead gives cyclo-co-oligomerization products. 

The cyclo-co-oligomerization of 1,3-dienes with alkynes is characterized by the relative ease with which rings are formed and by the possibility of incorporation of more than one alkyne molecule (Scheme 6). 

The cyclo-co-oligomerization of 2 moles of butadiene and 1 mole of ethylene also was catalyzed by a Ziegler combination, Ni(acac)2-Et2A10Et, to give cis-trans-1,5-cyclodecadiene, equation (7-7). A related linear co-... 

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