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Grignard Reagents and Products Formed

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A. Give the reaction scheme, showing the products formed (before hydrolysis) when one equivalent of ethylmagnesium bromide is treated with one equivalent of 5-hydroxy-2pentanone. Does addition of two equivalents of Grignard reagent to this yield a different product(s)? If so, give the structure(s).

B. Explain why Grignard reagents cannot be prepared from an organic halide that also contains a hydroxyl, a carboxyl, a thiol, or amino group.

C. What would be the final product of the reaction between methyl benzoate and two equivalents of ethylmagnesium bromide?

D. Consider the same reaction as in the case of question C except that it is carried out with ethyl benzoate. What product would be expected in this case?

E. Grignard reagents may be used to prepare other organometallic reagents, for example, ethylmagnesium bromide with cadmium chloride to yield diethylcadmium.

2CH3CH2MgCl + CdCl2 ---->(CH3CH2)2Cd+2MgCl2

Indicate the product of the following reactions and name the organometallic product.
1. 4CH3MgCl+SiCl4----> ?
2. C6H5MgCl+HgCl2----> ?

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Solution Preview

For these questions, a little explanation about Grignard reagents is required. Grignard reagents, are extremely useful in syntheses, for forming carbon, carbon bonds. They are so because they make a great nucleophile out of a carbon, which can attack any carbonyl carbon in the area to form a new carbon ...

Solution Summary

Structure drawings are included in attached power point presentation.

See Also This Related BrainMass Solution

Aldol condensations and Grignard reagents

1. "Crossed" or "mixed" aldol condensations are practical for synthesis, if one of the aldehydes (or ketones) has no alpha-hydrogen atoms. Explain.

2. In the aldol condensation using the conditions of this experiment, why might it be essential that the benzaldehyde contain no benzoic acid?

3. What hydrocarbon would you expect to obtain by the action of water on each of the Grignard reagents listed below?
a. Butylmagnesium bromide
b. sec-Butylmagnesium bromide
c. iso-Butylmagnesium bromide
d. tert-Butylmagnesium bromide

4. What product would each of the Grignard reagents in the previous question yield when treated with D2O?

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