Cyclopentadienide anions review

A stirred suspension of thallous cyclopentadienide (prepared from cyclopenta-diene, thallous sulfate, and KOH under No, Y >91%) in dry ether treated gradually at -20° under N2 with monochloromethyl ether, after 5 hrs. the crude intermediate isolated, allowed to react 18 hrs. at 0° with 4 equivalents 2-dilor-acrylonitrile and cupric fluoroborate, the resulting crude bicyclic chloronitriie dissolved in dimethyl sulfoxide, and treated 1.5 hrs. at 30-35° with aq. KOH product. Overall Y 50-55%. E. J. Corey, U. Koelliker, and J. Neuffer, Am. Soc. 93, 1489 (1971) f. e. s. ibid. 93, 1491 electrophilic substitution of cyclopentadienide anions, review, s. M. I. Rybinskaya and L. M. Korneva, Russ. Chem. Rev. 40, 247 (1971) (Eng. transl.). 

C-alkylation 26,718 Cyclopentadienide anions, substitution, electrophilic, review 26,718 Cyclopentane ring... 

Boratabenzenes represent a second important class of unsaturated boracycles. " While the dicoordinate borabenzene itself has not yet been reported, many Lewis base adducts, boratabenzene salts, and metal complexes are known. Boratabenzenes are six r-electron aromatic anions that resemble cyclopentadienides. For example, (V, A-diisopropyl-1-amino-boracyclohexadiene shows an acidity in DMSO which is similar to that of cyclopentadiene. The chemistry of boratabenzene ligands dates back to work by Herberich and Ashe in the early 1970s, which has been reviewed. However, many new achievements have been reported over the last decade and will be discussed in the following sections. 

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