Consecutive butylations on the cyclopentadienyl ring of the [(η5-C5H5)Fe(CO)2PPh 3]+ cation

Article abstract of DOI:10.1021/om960819e

The replacement of acidic hydrogen atoms in cyclopentadiene by alkyl groups would normally involve a repetitive deprotonation and then electrophilic alkylation. By means of η⁴-Fe complexation, one can reverse the polarity of cyclopentadiene and utilize multiple hydride abstraction Inucleophilic alky lotion cycles in the preparation of the polybutylcyclopentadienes in the neutral η⁴-Fe form and the corresponding cyclopentadienyl complexes in the cationic η⁵-Fe form.