Monoiodinated diene

Halogenolysis of zirconacyclopentadienes affords 1,4-dihalodienes (Eq. 2.14) [20]. Solvent effects on halogenolysis are remarkable. Indeed, whereas the iodination of zirconacyclopentadienes in THF with 2 equivalents of I2 affords mainly the monoiodinated diene, the diiododiene can be the major product in CH2C12. For example, 2,3,4,5-tetraethylzirco-nacyclopentadiene reacts with 2 equivalents of I2 in THF at room temperature to give the monoiodinated 3-iodo-4,5-diethylocta-3,5-diene 23 in 70% yield along with only an 18% yield of 3,6-diiodo-4,5-diethylocta-3,5-diene 24 (Eq. 2.14). 

Halogenolysis. Halogenolysis of zirconacyclopenta dienes (103) affords 1,4-dihalodienes. Whereas the iodina-tion of zirconacyclopentadienes in THF with 2 equivalents of I2 affords mainly the monoiodinated diene, the diiodo diene is the major product in CH2CI2. lodination carried out in... 

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