Grignard reagent with water

The reactions of Grignard reagents with water and alcohols are simply acid-base reactions => the Grignard reagent behaves as if it contained an carbanion. 

Hydrogenolysis of the toluene-4-sulfonate of an alcohol may be carried out with a nucleophilic hydride such as lithium aluminium hydride. There are also a series of radical methods based on the reduction of alkyl halides with tri- -butyltin hydride (BUjSnH). Finally, the source of the hydrogen may be the electrophilic proton, exemplified by the decomposition of organometallic reagents such as the Grignard reagent with water. 

Once again, the RD side-reaction proceeds by the protonation of arylnickel (or palladium) intermediates with water or other protic sources (see Chapter 3). The reaction is related to the quenching of Grignard reagent with water or alcohols to furnish a parent hydrocarbon. 

The reaction of a Grignard reagent with water can be put to useful purpose. For example, if heavy water (D2O) is used, deuterium (an isotope of hydrogen) can be substituted for a halogen. 

The reaction of the Grignard reagent with water is the basis of the analytical method used in this experiment. 

Reaction of a Grignard reagent with water is an example of an acid-base reaction (Section 1.7.6)... 

Indeed, it is endothermic by over 130 kJmoU This documents that the polar/ionic bond between magnesium and oxygen is exceptionally strong, a fact we already surmised by the vigor of the reaction of Grignard reagents with air and water. 

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. 

Dlalkylzincs are stable, distillable liquids that can be made by transmetallating Grignard reagents with zinc bromide. They are much less reactive than organolithium or organomagnesium compounds, but they are still rather basic and react with water to give zinc hydroxides and... 

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