Concept explainers
Interpretation:
The observation, Grignard reaction of cyclohexanone with tert-butylmagnesium bromide yields only about 1% of the expected addition product along with 99% unreacted cyclohexanone. If D3O+ is added to the reaction mixture after a suitable period, however, the unreacted cyclohexanone is found to have one deuterium atom incorporated into it, is to be explained.
Concept introduction:
Grignard reagents add to the carbonyl group in
Ketones exist in acid catalyzed reversible equilibrium with their enol tatomers.
To explain:
The observation, Grignard reaction of cyclohexanone with tert-butylmagnesium bromide yields only about 1% of the expected addition product along with 99% unreacted cyclohexanone. If D3O+ is added to the reaction mixture after a suitable period, however, the unreacted cyclohexanone is found to have one deuterium atom incorporated into it.
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Chapter 22 Solutions
ORGANIC CHEMISTRY-EBOOK>I<
- When cis-2-decalone is dissolved in ether containing a trace of HCl, an equilibrium is established with trans-2-decalone. The latter ketone predominates in the equilibrium mixture. Propose a mechanism for this isomerization and account for the fact that the trans isomer predominates at equilibrium.arrow_forwardThe following reactivity order has been found for the saponification of alkyl acetates by aqueous NaOH. Explain. CH3CO2CH3 > CH3CO2CH2CH3 > CH3CO2CH(CH3)2 > CH3CO2C(CH3)3arrow_forwardIn an aqueous solution containing sodium bicarbonate, aniline reacts quickly with bromine to give 2,4,6-tribromoaniline. Nitration of aniline requires very strong conditions, however, and the yields (mostly m-nitroaniline) are poor.Explain why nitration of aniline is so sluggish and why it gives mostly metasubstitution.arrow_forward
- How many stereoisomers are obtained from the reaction of 3-methyl-2-butanone with each of the following organometallic reagents followed by the addition of dilute acid? Name each stereoisomer. ethyllithium methylmagnesium bromidearrow_forwardShown below is the 1H NMR spectrum of the alkyl bromide used to make the phosphonium ylide that reacts with a ketone in a Wittig reaction to form acompound with molecular formula C11H14. What product is obtained from the Wittig reaction?arrow_forwardWhen cis-4-chlorocyclohexanol is treated with sodium hydroxide in ethanol, it gives mainly the substitution product trans-1,4-cyclohexanediol (1). Under the same reaction conditions, trans-4-chlorocyclohexanol gives 3-cyclohexenol (2) and the bicyclic ether (3). (a) Propose a mechanism for formation of product (1), and account for its configuration. (b) Propose a mechanism for formation of product (2). (c) Account for the fact that the bicyclic ether (3) is formed from the trans isomer but not from the cis isomer.arrow_forward
- Ethylene oxide is the starting material for the synthesis of 1,4-dioxane. Propose a mechanism for each step in this synthesis.arrow_forwardClaisen rearrangement of an allyl phenyl ether with substituent groups in both ortho positions leads to the formation of a para-substituted product. Propose a mechanism for the following rearrangement.arrow_forwardThe following sequence of steps converts (R)-2-octanol to (S)-2-octanol. Propose structural formulas for intermediates A and B, specify the configuration of each, and account for the inversion of configuration in this sequence.arrow_forward
- Nonconjugated , -unsaturated ketones, such as 3-cyclohexenone, are in an acid-catalyzed equilibrium with their conjugated , -unsaturated isomers. Propose a mechanism for this isomerization.arrow_forwardThe trimethylsilyl (TMS) protecting group is one of several silicon protecting groups for alcohols. For each reaction, draw the mechanism for the protection of (R)-3-bromo-1-butanol with the following silyl chlorides, using triethylamine as the base: (a) terf-butyldimethylsilyl chloride (TBS-C1] (b) triisopropylsilyl chloride (TEPS-C1) (c) triethylsilyl chloride (TES-C1)arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning
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