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Topic: How come the Grignard reagent is actaully consumed?  (Read 4947 times)

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Offline a confused chiral girl

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How come the Grignard reagent is actaully consumed?
« on: November 30, 2006, 04:43:34 PM »
when you add one equivalent of methylmagnesium iodide to ethyl acetoacetate, the Grignard reagent is consumed, but the only organice product obtained after H+ workup, the mixture is ethyl acetoacetate. Why is it like this, what happened to the Grignard reagent?
thank you!!
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Offline Yggdrasil

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Re: How come the Grignard reagent is actaully consumed?
« Reply #1 on: November 30, 2006, 06:46:15 PM »
What solvent are you using?  Do you have pure ethylacetoacetate or is there some ethyacetoacetic acid as well?
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Offline Custos

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Re: How come the Grignard reagent is actaully consumed?
« Reply #2 on: November 30, 2006, 07:05:13 PM »
The protons between the carbonyl groups of ethyl acetoacetate are relatively acidic. One equivalent of methyl Grignard is likely to abstract one proton (remember Grignards are both nucleophiles and strong bases) - which quenches the Grignard as methane. Aqueous work up gives ethyl acetoacetate back again.
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