Benzyl sigma complex

The resulting compound bears an OF group coimected to a benzylic position. This OH can be protonated under acidic conditions, followed by loss of a leaving group to give a resonance-stabilized, benzylic carbocation. This carbocation can then serve as an electrophile in an electrophilic aromatic substitution reaction. Phenol functions as the nucleophile and attacks the electrophile, giving a resonance-stabilized intermediate (sigma complex). Water can then serve as a... 

These observations show that despite the bulkiness of the benzyl groups in Zr (benzyl) 4, sufficient room is available for coordination of the monomer without displacing the benzyl group. This can be readily seen from the structure of Zr (benzyl) 4 represented by Fig. 2. We therefore write the initiation step for sigma-bonded complexes as follows... 

Mansuy, D. and M. Fontecave (1983). Reduction of benzyl halides by liver microsomes Formation of 478 nm-absorbing sigma-alkyl-ferric cytochrome P450 complexes. Biochem. Pharmacol. 32, 1871-1879. 

---