Of dilithium dianions

Table 1 lists preparations of Li radical anions, some of which are shown in Fig. 1. In addition to these, the ESR spectra of several polycyclic Li aromatic radical anions are recorded during the preparations of dilithium dianions discussed in subsection (ii). 

Examples of dilithium dianions in this group are collected in Table 2, where the products are represented with localized structures. 

The results of alkylations of ester enolates such as (126) with P-methyl and P-CH20R substituents (which have similar steric requirements) provide additional evidence that alkylation occurs anti to the more strongly electron-releasing P-substituent (Scheme 59). Presumably in (126) a lone pair of electrons on oxygen facilitates electron release by the P-carbon-7-carbon bond. 1110, an alkylation transition state such as (127) may obtain in such cases. Alkylations of dilithium dianions of 3-benzoylaminobutanoic acid esters have also been shown to give mainly the anti 2,3-disubstituted dia-stereomers. ... 

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See also in sourсe #XX -- [ , , , , , ]

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