POTASSIUM DERIVATIVES OF FLUORENE AS INTERMEDIATES IN THE PREPARATION OF C9-SUBSTITUTED FLUORENES: II. COMPARATIVE REACTIVITIES OF THE ALKALI METALS, LITHIUM, SODIUM, AND POTASSIUM, WITH FLUORENE IN GLYCOL DIMETHYL ETHER, GLYCOL DIETHYL ETHER, TETRAHYDROFURAN, AND DIOXANE

Abstract

In the solvents 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), tetrahydrofuran (THF), and dioxane, potassium reacts much more readily with fluorene than does sodium or lithium. Lithium is generally more reactive than is sodium. The order of effectiveness of the ethers is DME > DEE ≈ THF > dioxane. Although practically no reaction of these metals with fluorene occurs in toluene, the addition of small amounts of these ethers to toluene does accelerate such reaction. All three organometallic compounds are soluble in refluxing and cold (22°) DME, THF, and DEE except the 9-fluorenyllithium, which precipitates largely from cold DEE. The results are explained in terms of the relative electropositivities of the metals, their size, and the structure of the ethers. It is suggested that these ethers actually participate in the formation of the organometallic compound from the metal.Sodamide and lithium amide react as readily as or more readily than the metals with fluorene in DME to produce the organometallic compounds.Diphenylmethane and triphenylmethane react reasonably well with potassium in DME, but too slowly with lithium and sodium to be useful.