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Reaction of Grignard reagents with esters
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+ Biochemistry
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Michael Zorn
Reaction of Grignard reagents with esters
Yes, that is exactly what happens. And since ketones are typically more reactive than esters, you should expect that the tertiary alcohol (after workup) will be the predominant product.
In order to access the ketone, add the Grignard to a nitrile, which will give an imine (after protonation) that can be hydrolyzed to a ketone. Alternatively, add the Grignard to an aldehyde and oxidize the resulting alcohol to the ketone.
Yes, that is exactly what happens. And since ketones are typically more reactive than esters, you should expect that the tertiary alcohol (after workup) will be the predominant product.
In order to access the ketone, add the Grignard to a nitrile, which will give an imine (after protonation) that can be hydrolyzed to a ketone. Alternatively, add the Grignard to an aldehyde and oxidize the resulting alcohol to the ketone.
Reaction of a Grignard reagent with an ester is a standard method for producing tertiary alcohols where at least two of the substituents (the "$\small\ce{R_2}$" group attached to the Grignard) are the same. Judicious choice of the starting ester allows for the preparation of a tertiary alcohol where all 3 substituents are the same. Alternately, you could react 3 equivalents of the Grignard with a cheap dialkyl carbonate (a "double" ester, if you will) to obtain a tertiary alcohol where all 3 groups are the same.
Typically a slight excess of Grignard reagent is used and the tertiary alcohol is produced after acid work-up. If an excess of Grignard is not used then a mixture (ugh!) of ester, intermediate ketone and alcohol may result.
Reaction of a Grignard reagent with an ester is a standard method for producing tertiary alcohols where at least two of the substituents (the "$\small\ce{R_2}$" group attached to the Grignard) are the same. Judicious choice of the starting ester allows for the preparation of a tertiary alcohol where all 3 substituents are the same. Alternately, you could react 3 equivalents of the Grignard with a cheap dialkyl carbonate (a "double" ester, if you will) to obtain a tertiary alcohol where all 3 groups are the same.
Typically a slight excess of Grignard reagent is used and the tertiary alcohol is produced after acid work-up. If an excess of Grignard is not used then a mixture (ugh!) of ester, intermediate ketone and alcohol may result.
Oh, I thought the reactant in the top line of your drawing was a carboxylate anion. I guess thats not a minus sign but rather a bond where you just didnt draw the alkyl group on the end.More
Yes, that is exactly what happens. And since ketones are typically more reactive than esters, you should expect that the tertiary alcohol (after workup) will be the predominant product.
In order to access the ketone, add the Grignard to a nitrile, which will give an imine (after protonation) that can be hydrolyzed to a ketone. Alternatively, add the Grignard to an aldehyde and oxidize the resulting alcohol to the ketone.
Yes, that is exactly what happens. And since ketones are typically more reactive than esters, you should expect that the tertiary alcohol (after workup) will be the predominant product.
In order to access the ketone, add the Grignard to a nitrile, which will give an imine (after protonation) that can be hydrolyzed to a ketone. Alternatively, add the Grignard to an aldehyde and oxidize the resulting alcohol to the ketone.
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Reaction of a Grignard reagent with an ester is a standard method for producing tertiary alcohols where at least two of the substituents (the "$\small\ce{R_2}$" group attached to the Grignard) are the same. Judicious choice of the starting ester allows for the preparation of a tertiary alcohol where all 3 substituents are the same. Alternately, you could react 3 equivalents of the Grignard with a cheap dialkyl carbonate (a "double" ester, if you will) to obtain a tertiary alcohol where all 3 groups are the same.
Typically a slight excess of Grignard reagent is used and the tertiary alcohol is produced after acid work-up. If an excess of Grignard is not used then a mixture (ugh!) of ester, intermediate ketone and alcohol may result.
Reaction of a Grignard reagent with an ester is a standard method for producing tertiary alcohols where at least two of the substituents (the "$\small\ce{R_2}$" group attached to the Grignard) are the same. Judicious choice of the starting ester allows for the preparation of a tertiary alcohol where all 3 substituents are the same. Alternately, you could react 3 equivalents of the Grignard with a cheap dialkyl carbonate (a "double" ester, if you will) to obtain a tertiary alcohol where all 3 groups are the same.
Typically a slight excess of Grignard reagent is used and the tertiary alcohol is produced after acid work-up. If an excess of Grignard is not used then a mixture (ugh!) of ester, intermediate ketone and alcohol may result.
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