Multiple Choice Which of the following reactions will NOT produce a 3° alcohol as the major, organic product?360views
Textbook QuestionLOOKING AHEAD We discuss the reaction of Grignard reagents (organomagnesium compounds) to ketones in Chapter 17. Mechanistically, the reaction proceeds by the nucleophilic addition of a methyl carbanion to the electrophilic carbon of the carbonyl, breaking the C―Oπ bond, resulting in an alkoxide intermediate that is subsequently protonated to produce the 3° alcohol. (a) Why does this reaction produce a racemic mixture of 3° alcohols?401views
Textbook QuestionLOOKING AHEAD We discuss the reaction of Grignard reagents (organomagnesium compounds) to ketones in Chapter 17. Mechanistically, the reaction proceeds by the nucleophilic addition of a methyl carbanion to the electrophilic carbon of the carbonyl, breaking the C―Oπ bond, resulting in an alkoxide intermediate that is subsequently protonated to produce the 3° alcohol. (b) Why, when the substrate is modified slightly, does the reaction result in an excess of one stereoisomer?316views
Textbook QuestionLOOKING AHEAD CHAPTERS 8, 17 In Chapters 8 and 17 we learn two reactions for the synthesis of the alcohol shown. (a) Show a mechanism for each of the reactions. (b) If you were designing a synthetic route, which would be considered more sustainable? Consider all factors. [Assume the starting organic molecules are equally green.] <IMAGE> <IMAGE>355views
Textbook QuestionStarting from bromobenzene and any other reagents and solvents you need, show how you would synthesize the following compounds. Any of these products may be used as starting materials in subsequent parts of this problem. (b) 1-phenylpropene503views
Textbook QuestionWhich of the following compounds are suitable solvents for Grignard reactions? (a) n-hexane (b) CH3-O-CH3 (c) CHCl3 (d) cyclohexane (e) benzene (f) CH3OCH2CH2OCH3 (g) (h) <1138views
Textbook QuestionDraw the organic products you would expect to isolate from the following reactions (after hydrolysis). (c) (d) 927views
Textbook QuestionA formate ester, such as ethyl formate, reacts with an excess of a Grignard reagent to give (after protonation) secondary alcohols with two identical alkyl groups. (b) Show how you would use reactions of Grignard reagents with ethyl formate to synthesize the following secondary alcohols (i) pentan-3-ol (ii) diphenylmethanol (iii) trans,trans-nona-2,7-dien-5-ol1360views
Textbook QuestionShow how you would use Grignard syntheses to prepare the following alcohol from the indicated starting material and any other necessary reagents. (a) octan-3-ol from hexanal, CH3(CH2)4CHO902views
Textbook QuestionOften, compounds can be synthesized by more than one method. Show how this 3° alcohol can be made from the following: (a) two different ketones665views
Textbook QuestionA formate ester, such as ethyl formate, reacts with an excess of a Grignard reagent to give (after protonation) secondary alcohols with two identical alkyl groups. (a) Propose a mechanism to show how the reaction of ethyl formate with an excess of allylmagnesium bromide gives, after protonation, hepta-1,6-dien-4-ol. 1151views
Textbook QuestionShow how to make these deuterium-labeled compounds, using CD3MgBr and D2O as your sources of deuterium, and any non-deuterated starting materials you wish. (d) Ph(CD3)2COD567views
Textbook QuestionShow how to make these deuterium-labeled compounds, using CD3MgBr and D2O as your sources of deuterium, and any non-deuterated starting materials you wish. (b) CH3C(OH)(CD3)2845views
Textbook QuestionShow how to make these deuterium-labeled compounds, using CD3MgBr and D2O as your sources of deuterium, and any non-deuterated starting materials you wish. (a) CH3CH(OD)CD3787views1comments
Textbook QuestionShow how you would synthesize the following: (a) 2-phenylethanol by the addition of formaldehyde to a suitable Grignard reagent1054views
Textbook QuestionAcetylide ions also add to ethylene oxide much like Grignard and organolithium reagents. Predict the products obtained by adding the following acetylide ions to ethylene oxide, followed by a dilute acid workup. (a) (b) 694views
Textbook QuestionShow how you would synthesize the following alcohol by adding Grignard reagents to ethylene oxide. (a) 2-phenylethanol659views
Textbook QuestionShow how you would add Grignard reagent to acid chloride or ester to synthesize the following alcohol. (a) Ph3C-OH903views
Textbook QuestionShow how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone (b) Ph3COH912views
Textbook QuestionShow two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde. (a) 832views
Textbook QuestionShow how you would synthesize the following primary alcohol by adding an appropriate Grignard reagent to formaldehyde (a) 766views
Textbook QuestionShow how you would synthesize the following compound from alkyl halides, vinyl halides, and aryl halides containing no more than six carbon atoms. (c) trans-oct-3-ene488views
Textbook QuestionShow how you would synthesize the following compound from alkyl halides, vinyl halides, and aryl halides containing no more than six carbon atoms. (a) octane481views
Textbook QuestionPredict the major products of the following reactions, including stereochemistry where appropriate. (h) cyclooctylmethanol + CH3CH2MgBr (i) potassium tert-butoxide + methyl iodide (j) sodium methoxide + tert-butyl iodide1028views
Textbook QuestionWhich of the following alkyl halides could be successfully used to form a Grignard reagent?692views
Textbook QuestionHow could the following compounds be prepared, using cyclohexene as a starting material? d.360views
Textbook QuestionA laboratory student added 1-bromobutane to a flask containing dry ether and magnesium turnings. An exothermic reaction resulted, and the ether boiled vigorously for several minutes. Then she added acetone to the reaction mixture and the ether boiled even more vigorously. She added dilute acid to the mixture and separated the layers. She evaporated the ether layer, and distilled a liquid that boiled at 143 °C. GC–MS analysis of the distillate showed one major product with a few minor impurities. The mass spectrum of the major product is shown here. (a) Draw out the reactions that took place and show the product that was formed.623views
Textbook QuestionStarting with cyclohexane, how could the following compounds be prepared? e. 600views
Textbook Question(•••) THINKING AHEAD A chemist attempted the reaction below, one we introduce in Chapter 17, expecting the reaction between a strong nucleophile and a ketone in water to give an alkoxide product. (a) Why did the reaction fail? (b) How could the reaction conditions be changed to give a successful reaction?<IMAGE>326views
Textbook QuestionGive the expected products of the following reactions. Include a protonation step where necessary. (a) 2,2-dimethyloxirane + isopropylmagnesium bromide (b) propylene oxide + n-butyllithium (c) cyclopentyloxirane + ethyllithium677views
Textbook QuestionPredict the product of the diorganocuprate cross-coupling reactions shown. (a)354views
Textbook QuestionPredict the product of the diorganocuprate cross-coupling reactions shown. (b)421views
Textbook QuestionBased on the stereochemical result alone, how can you tell that this reaction does not proceed by an Sₙ2 mechanism?327views
Textbook Question(•••) LOOKING AHEAD A chemist failed to generate the alcohol using the reaction shown here. (a) Suggest a reason why this reaction did not work as written. (b) How could the reaction conditions be modified to allow formation of the product? [Answer in general terms; we explain how to fix this in Chapter 17.]415views
Textbook Question(••) In lieu of quenching the product of Grignard addition to a carbonyl with acid, alkyl halides can be added directly to generate ether products. Predict the product and show the mechanism of this process.317views
Textbook QuestionPredict the products formed when cyclohexanone reacts with the following reagents. (f) PhMgBr and then mild H3O+1107views
Textbook QuestionPredict the products of the following reactions. (d) product of (c) + cyclopentylmagnesium bromide, then acidic hydrolysis1063views
Textbook QuestionYou might expect that aldehydes and ketones (Chapter 18) could undergo the addition/elimination mechanism. With strong nucleophiles, however, nucleophilic addition is the only outcome. Why?340views
Textbook QuestionBeginning with an amide, two different pathways produce the same compound. Predict the product of these two pathways.342views
Textbook Question16.42 (••) Which of the following solvents are reasonable choices for a Grignard reaction? Justify your choices. [Hint: Carbonyls are good electrophiles (see Chapter 17).]<IMAGE> <IMAGE> <IMAGE> <IMAGE>291views
Textbook QuestionA student, when solving the following 'predict-the-product' question, made a common mistake by writing the answer shown here. Explain why this reaction would not work as written.<IMAGE>311views
Textbook QuestionDimerization is a side reaction that occurs during the preparation of a Grignard reagent. Propose a mechanism that accounts for the formation of the dimer.<IMAGE>333views
Textbook QuestionList three different sets of reagents (each set consisting of a carbonyl compound and a Grignard reagent) that could be used to prepare each of the following tertiary alcohols:a. <IMAGE>349views
Textbook QuestionA student added an equivalent of 3,4-epoxy-4-methylcyclohexanol to a solution of methylmagnesium bromide in diethyl ether, and then added dilute hydrochloricacid. He expected that the product would be 1,2-dimethyl-1,4-cyclohexanediol. He did not get any of the expected product. What product did he get?<IMAGE>336views
Textbook QuestionList three different sets of reagents (each set consisting of a carbonyl compound and a Grignard reagent) that could be used to prepare each of the following tertiary alcohols:b. <IMAGE>326views
Textbook QuestionAddition of 1-bromobut-2-ene to magnesium metal in dry ether results in formation of a Grignard reagent. Addition of water to this Grignard reagent gives a mixture of but-1-ene and but-2-ene (cis and trans). When the Grignard reagent is made using 3-bromobut-1-ene, addition of water produces exactly the same mixture of products in the same ratios. Explain this curious result267views
Textbook QuestionPropose a mechanism for the reaction of acetyl chloride with phenylmagnesium bromide to give 1,1-diphenylethanol<IMAGE>337views
Textbook QuestionTwo of the methods for converting alkyl halides to carboxylic acids are covered in Sections 20-8B and 20-8C. One is formation of a Grignard reagent followed by addition of carbon dioxide and then dilute acid. The other is substitution by cyanide ion, followed by hydrolysis of the resulting nitrile. For each of the following conversions, decide whether either or both of these methods would work, and explain why. Show the reactions you would use.(e) <IMAGE>(f) <IMAGE>231views
Textbook QuestionGrignard reagents react slowly with oxetane to produce primary alcohols. Propose a mechanism for this reaction, andsuggest why oxetane reacts with Grignard reagents even though most ethers do not.<IMAGE>232views
Textbook QuestionDraw the organic products you would expect to isolate from the following reactions (after hydrolysis).(f) <IMAGE> (g) <IMAGE>253views
Textbook QuestionShow how you would use Grignard syntheses to prepare the following alcohol from the indicated starting material and any other necessary reagents.(g) cyclopentylphenylmethanol from benzaldehyde (Ph-CHO)223views
Textbook QuestionShow how to make these deuterium-labeled compounds, using CD3MgBr and D2O as your sources of deuterium, and any non-deuterated starting materials you wish.(c) CD3CH2CH2OH272views
Textbook QuestionOften, compounds can be synthesized by more than one method. Show how this 3° alcohol can be made from thefollowing:<IMAGE>(c) an ester286views
Textbook QuestionShow how you would synthesize the following primary alcohol by adding an appropriate Grignard reagent to formaldehyde(c) <IMAGE>221views
Textbook QuestionShow two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde.(c) <IMAGE>289views
Textbook QuestionShow how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone(c) 1-ethylcyclopentanol216views
Textbook QuestionShow how you would add Grignard reagent to acid chloride or ester to synthesize the following alcohols.(c) dicyclohexylphenylmethanol213views
Textbook QuestionShow how you would synthesize the following alcohol by adding Grignard reagents to ethylene oxide.(c) <IMAGE>215views
Textbook QuestionShow how you would use Grignard syntheses to prepare the following alcohol from the indicated starting material and any other necessary reagents.(d) 2-cyclohexylethanol from bromocyclohexane229views
Textbook QuestionShow how this 1° alcohol can be made from the following:<IMAGE>(e) an alkene(f) ethylene oxide256views
Textbook QuestionShow how you would synthesize the following primary alcohol by adding an appropriate Grignard reagent to formaldehyde(b) <IMAGE>226views
Textbook QuestionShow how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone(d) 2-cyclopentylpentan-2-ol185views
Textbook QuestionPoint out the flaws in the following incorrect Grignard syntheses.(c) <IMAGE>(d) <IMAGE>311views
Textbook QuestionA variety of organometallics, which as strong nucleophiles can react with epoxides, are introduced in Chapter 16. Predict the product of these reactions. [Hint: Assume the carbon–metal bond in each is ionic, with the carbon possessing the negative charge.] (b)334views
Textbook QuestionAddition to an epoxide occurs via an Sₙ2 reaction, but the stereochemistry of the epoxide is retained in the following reaction. Why?200views
Textbook QuestionShow how you would synthesize the following: (f) 2,5-dimethylhexane from a four-carbon alkyl halide789views
Textbook QuestionPredict the products of the following reactions. (a) allyl bromide + cyclohexyl magnesium bromide820views1comments
Textbook QuestionShow how the reaction of an allylic halide with a Grignard reagent might be used to synthesize the following hydrocarbons. (c) 1-cyclopentylpent-2-ene673views
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