Lewis bases deaggregation

Since Lewis base additives and basic solvents such as tetrahydrofuran are known to deaggregate polymeric organolithium compounds, (21,23,26) it was postulated that ketone formation would be minimized in the presence of sufficient tetrahydrofuran to effect dissociation of the aggregates. In complete accord with these predictions, it was found that the carbonation of poly(styryl)lithium (eq. 9), poly(isoprenyl)-lithium, and poly(styrene-b-isoprenyl)lithium in a 75/25 mixture (by volume) of benzene and tetrahydrofuran occurs quantitatively to produce the carboxylic acid chain ends (8 ). 

Fig. 10.2. The structures of alkyllithium compounds in solution I Deaggregation of the alkyllithium structures, as preferred in the solid state, usually occurs when Lewis bases are added or alkyllithium compounds are dissolved in Lewis-basic solvents. By the way, this process is accompanied by a decrease of entropy, i.e., occuring more at low than at higher temperatures.

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