Grignard compounds tetrahydrofuran

Drahowzal et al.102 obtained good yields of the so-called individual Grignard compounds by carrying out the reaction in benzene to which a small amount of a 10% solution of anhydrous aluminum chloride in tetrahydrofuran had been added. 

The alkine bromides (XI) were obtained according to Osbond and Wickens (26) by reacting the alldne bromides (VI) with the di-Grignard compound of propargylic alcohol in tetrahydrofuran catalyzed by cuprous chloride. In this way substances were prepared (Xla)-(XId) ... 

Anionic polymerizations are initiated in polar systems by bases and Lewis bases. For example, alkali metals, alcoholates, metal ketyls, metal alkyls, amines, phosphines, and Grignard compounds act as initiators. However, the polymerization mechanism does not depend on the nature of the initiator alone. For example, tertiary amines and phosphines do not only initiate anionic polymerizations under certain conditions, they can also initiate zwitterion polymerizations. In addition, polyinsertions can proceed in less polar systems. Thus, anionic polymerizations are often carried out in polar solvents. Ethers and nitrogen compounds, such as tetrahydrofuran, ethylene glycol dimethyl ether (glyme), diethylene glycol dimethyl ether (diglyme), pyridine, and ammonia are most commonly used. 

A soln. of propionaldehyde in ether or tetrahydrofuran added to 2 moles of ice-cooled l-diethylamino-2-propen-2-ylmagnesium bromide soln. prepared from l-diethylamino-2-bromo-2-propene and Mg in tetrahydrofuran in the presence of a crystal of iodine l-diethylamino-2-methylene-3-pentanol. Y 70%.—The double bond prevents a possible -elimination, and stable Grignard compounds are obtained. F. e. s. J. Ficini, G. Sarrade-Loucheur, and H. Normant, Bl. 1962, 1219. 

Grignard reagents (Section 14 4) Grignard reagents are prepared in a manner similar to that used for organolithium compounds Di ethyl ether and tetrahydrofuran are appro priate solvents... 

By reaction of an a-halo ester 1 with zinc metal in an inert solvent such as diethyl ether, tetrahydrofuran or dioxane, an organozinc compound 2 is formed (a Grignard reagent-like species). Some of these organozinc compounds are quite stable even a structure elucidation by x-ray analysis is possible in certain cases ... 

The lesser known four-membered cyclic ether, oxacyclobutane (oxe-tane), (CH2)30, also is cleaved readily, but less so than oxacyclopropane. Oxacyclopentane (oxolane, tetrahydrofuran) is a relatively unreactive water-miscible compound with desirable properties as an organic solvent. It often is used in place of diethyl ether in Grignard reactions and reductions with lithium aluminum hydride. 

Coupling to produce dimeric product was a side reaction in these systems also, e.g. 75 % dimer formation was reported for poly(styryl)lithium and 23 % dimer formation with the poly(styryl)-Grignard reagent 326). However, it should be noted that the only reported characterizations of these reactions were size exclusion chromatography traces and silver catalyzed polymerization of tetrahydrofuran using the polymeric halogen compounds as co-initiator. 

Bis[4-acetylphenyl] Ditellurium [Grignard Method] 1 The Grignard reagent is prepared from 4.09 g (0.0165 mol) of the 1,2-dihydroxycthane acetal of 4-acetylbromobenzene in 50 ml of tetrahydrofuran and the solution cooled to 0°. 3.15 g (0.025 mol) of powdered tellurium are added and the mixture is stirred in the flask, which is open to the atmosphere, for 10-15 h. 4 Molar aqueous hydrochloric acid is added to pH 2.5 and the ditcllurium compound is extracted with three 50 ml portions of diethyl ether. The combined extracts arc filtered, dried with sodium sulfate, the solvent is evaporated, and the residue is recryslallized from diethyl ether yield 0.36 g (9%, based on bromoacetal) m.p. 104-106°. 

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