The catalytic action of anionic catalysts. Part XIV. The reaction of n-butyl-lithium with fluorene in tetrahydrofuran studied by a new vacuum-type stopped-flow apparatus

Abstract

We have built a new vacuum-type stopped-flow apparatus to study the reactions of highly reactive anionic species. Reactions having a half-life as low as 5 milliseconds can be followed from room temperature to –80 °C under conditions which rigorously exclude impurities.

Our first measurements by use of this new method have been carried out on the reaction of n-butyl-lithium with fluorene in tetrahydrofuran. The thermodynamic constants of activation determined for this reaction are: ΔG^‡ 14·1 kcal mol^–1, ΔH^‡ 4·7 kcal mol^–1, and ΔS^‡–31·2 cal mol^–1 K^–1.