Diethyl ether Grignard reagent with

After treatment of the Grignard reagent with chlorine, the solid which separated exploded when shaken [1], This solid was not seen later, using either diethyl ether or THF as solvent [2], (The explosive solid could have been magnesium hypochlorite if moisture were present in the chlorine.)... 

Tetraallyluranium [143, 144) and tetra(2-methylallyl)-uranium(IV) [145) are prepared by the reaction of the Grignard reagents with uranium tetrachloride in diethyl ether. The PMR spectra of these temperature-sensitive compounds are listed in Table 7. The AMgXa [146) pattern exhibited by tetraallyluranium is typical of the symmetrical jr-allyl structure in Fig. 14. The spectrum of tetra-... 

A solution of 156 g. (1.32 moles) of diethyl carbonate (Note 3) in 200 cc. of ether is added to the Grignard reagent, with rapid stirring, over a period of approximately three hours. The reaction is vigorous and the ether refluxes continually. After all of the diethyl carbonate has been added, the flask is heated on a water bath and stirring is continued for another hour. 

The last consideration is the reactivity of the Grignard reagent with the solvent itself. Deleterious reactions of the Grignard reagent with ethereal solvents occurs only under extreme conditions and has been observed, to some extent, in diethyl ether, di-n-butyl ether, THF, r-butylmethyl ether, anisole (155°C), DME, and allylphenyl ether [Eq. (7) 19-24], Since these reactions occur only under extreme conditions, the ethereal solvents are preferred because of the high Grignard reagent solubility (up to 4 M). 

These compounds were also proposed as intermediates, formed in reactions of Grignard compounds with ketones [90,91]. Several complexed organomagnesium reagents were observed in the reaction of dimethylmagnesium with an excess of 2-methylbenzophenone [92] in diethyl ether (Scheme 32). With the reaction of both methyl groups in the organomagnesium reagent, yields of the product were quantitative. 

Table 1 Rate Constants for Reactions of Various Grignard Reagents with Benzophenone and Acetone (fcobs/sec ) [2b] (0.50 M RMgX with 0.05 M Ketone in Diethyl Ether at 20 C) and with Carbon Dioxide mol sec ) [12]...

Table 7 Relative Reactivities of Ethyl Grignard Reagents with 1-Hexyne in Diethyl Ether in the Presence of Tertiary Amines [31]...

Much improved yields of ketones, formed by reaction of Grignard reagents with nitriles 33, have been obtained when reactions were performed in benzene containing 1 Eq of diethyl ether, rather than in diethyl ether alone [51]. Under the modified conditions, it is postulated that reaction occurs through a species in which the nitrile has displaced a diethyl ether solvent molecule from a dimeric Grignard species. 

The doubly allylic di-Grignard reagent 172, generated in situ from l,4-dibromo-2-butene and magnesium in diethyl ether, was reacted with dimethyldichlorosilane to yield silacyclopentene 173 [Eq. (76)], in 60% yield [141] butadiene can also be formed from... 

In the same way methyllithium in diethyl ether and butyllithium in hexane give predominantly lithium-hydrogen exchange and very little addition. This contrasts strongly with the reaction of Grignard reagents with cyclopropanes, which gives efficient addition vide supra). 

In 1971 a study was made of the kinetics of the reactions of Grignard reagents with ben/ophenone using diethyl ether as the solvent 52. Included was an investigation of the products formed in the reaction. For r-bulylmagnesium chloride it was found that 50% of the product was the 1.4-dihydro-4-/-butylbenz.ophcnone. 44 4 was normal 1.2-addilion product and 69 was benzopinacol. 1.6-addilion to unstibslituied benzophenone had never been observed before, evidently because tile product easily oxidizes in air and decomposes thermally below IOO C. 

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