Interpretation:
The effect on the Grignard reagent in the reaction of one equivalent of methylmagnesium iodide with ethyl acetoacetate is to be explained and the location of deuterium in the recovered ethyl acetoacetate is to be identified.
Concept introduction:
Grignard reagents react with
The Grignard reagent adds to the carbonyl group of aldehydes and ketones due to electronegativity difference between carbon and oxygen.
A molecule that consists of a ketone group on the
Diethyl malonate and ethyl acetoacetate are some examples of
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- The following bicyclic ketone has two -carbons and three -hydrogens. When this molecule is treated with D2O in the presence of an acid catalyst, only two of the three -hydrogens exchange with deuterium. The -hydrogen at the bridgehead does not exchange. How do you account for the fact that two -hydrogens do exchange but the third does not? You will find it helpful to build models of the enols by which exchange of -hydrogens occurs.arrow_forwardThe formation of Br2 from NBS first involves the reaction of NBS with HBr to form an iminol intermediate and molecular bromine. The intermediate then undergoes acid-catalyzed tautomerism to form succinimide, the byproduct of the reaction. Propose a curved-arrow mechanism for the conversion of NBS into succinimide that also accounts for the formation of Br2.arrow_forwardThe ketone shown was prepared in a three-step sequence from ethyl trifluoroacetate. The first step in the sequence involved treating ethyl trifluoroacetate with ammonia to give compound A. Compound A was in turn converted to the desired ketone by way of compound B. Fill in the missing reagents in the sequence shown, and give the structures of compounds A and B.arrow_forward
- Compelling evidence for the existence of a tetrahedral intermediate in nucleophilic acyl substitution was obtained in a series of elegant experiments carried out by Myron Bender in 1951. The key experiment was the reaction of aqueous −OH with ethyl benzoate (C6H5COOCH2CH3) labeled at the carbonyl oxygen with 18O. Bender did not allow the hydrolysis to go to completion, and then examined the presence of a label in the recovered starting material. He found that some of the recovered ethyl benzoate no longer contained a label at the carbonyl oxygen. With reference to the accepted mechanism of nucleophilic acyl substitution, explain how this provides evidence for a tetrahedral intermediate.arrow_forwardCompelling evidence for the existence of a tetrahedral intermediate in nucleophilic acyl substitution was obtained in a series of elegant experiments carried out by Myron Bender in 1951. The key experiment was the reaction of aqueous−OH with ethyl benzoate (C6H5COOCH2CH3) labeled at the carbonyl oxygen with 18O. Bender did not allow the hydrolysis to go to completion, and then examined the presence of a label in the recovered starting material. He found that some of the recovered ethyl benzoate no longer contained a label at the carbonyl oxygen. With reference to the accepted mechanism of nucleophllic acyl substitution, explain how this provides evidence for a tetrahedral intermediate.arrow_forwardGive the structure of the product formed on reaction of ethyl acetoacetate with each of the following: (a) 1-Bromopentane and sodium ethoxide (b) Saponification (basic hydrolysis) and decarboxylation of the product in part (a) (c) Methyl iodide and the product in part (a) treated with sodium ethoxide (d) Saponification and decarboxylation of the product in part (c) (e) 1-Bromo-3-chloropropane and one equivalent of sodium ethoxide (f) Product in part (e) treated with a second equivalent of sodium ethoxide (g) Saponification and decarboxylation of the product in part (f) (h) Phenyl vinyl ketone and sodium ethoxide (i) Saponification and decarboxylation of the product in part (h)arrow_forward
- Electrophilic nitration of benzoic acid gives almost exclusively 3-nitrobenzoic acid. By drawing the appropriate resonance forms of the intermediate cations resulting from attack of [NO2]+, explain this result.arrow_forwardTwo isomers, A and B, of molecular formula C5H8 undergo catalytic hydrogenation with hydrogen gas and palladium on carbon to form the same C5H10 product. On ozonolysis followed by treatment with hydrogen peroxide (H2O2), isomer A gave a product of molecular formula C5H8O4 that has two carboxylic acid groups in it whereas isomer B gave a product of molecular formula C5H8O3 that contains a carboxylic acid group and a ketone group. Which of the following isomeric pairs best match this data?arrow_forwardTwo isomers, A and B, of molecular formula C5H8 undergo catalytic hydrogenation with hydrogen gas and palladium on carbon to form the same C5H10 product. On ozonolysis followed by treatment with hydrogen peroxide (H2O2), isomer A gave a product of molecular formula C5H8O4 that has two carboxylic acid groups in it whereas isomer B gave a product of molecular formula C5H8O3 that contains a carboxylic acid group and a ketone group. What is the isometric pair of A and B that corresponds?arrow_forward
- The base-promoted rearrangement of an -haloketone to a carboxylic acid, known as the Favorskii rearrangement, is illustrated by the conversion of 2-chlorocyclohexanone to cyclopentanecarboxylic acid. It is proposed that NaOH first converts the a-haloketone to the substituted cyclopropanone shown in brackets and then to the sodium salt of cyclopentanecarboxylic acid. (a) Propose a mechanism for base-promoted conversion of 2-chlorocyclohexanone to the proposed intermediate. (b) Propose a mechanism for base-promoted conversion of the proposed intermediate to sodium cyclopentanecarboxylate.arrow_forwardThe following questions pertain to the esters shown and behavior under conditions of the Claisen condensation.(a) Two of these esters are converted to β-keto esters in good yield on treatment with sodium ethoxide and subsequent acidification of the reaction mixture. Which two are these? Write the structure of the Claisen condensation product of each one. (b) One ester is capable of being converted to a β-keto ester on treatment with sodium ethoxide, but the amount of β-keto ester that can be isolated after acidification of the reaction mixture is quite small. Which ester is this? (c) One ester is incapable of reaction under conditions of the Claisen condensation. Which one? Why?arrow_forwardAcid-catalyzed hydrolysis of HOCH2CH2C(CH3)2CN forms compound A (C6H10O2). A shows a strong peak in its IR spectrum at 1770 cm-1 and the following signals in its 1H NMR spectrum: 1.27 (singlet, 6 H), 2.12 (triplet, 2 H), and 4.26 (triplet, 2 H) ppm. Draw the structure for A and give a stepwise mechanism that accounts for its formation.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningEBK A SMALL SCALE APPROACH TO ORGANIC LChemistryISBN:9781305446021Author:LampmanPublisher:CENGAGE LEARNING - CONSIGNMENT