Interpretation:
The reason has to be explained for formation of racemic mixture of 2-bromooctane when the reaction of NaBr with (R)-2-Bromooctane.
Concept introduction:
SN2 reaction:
The alcohol is reaction with acids like hydrochloric acid or hydrobromic acid, the bromine atom attacks back side of the carbon atoms in simultaneous manner and which is bearing alcohol group which yield the corresponding product.
Example:
The tosylated compound is reaction with sodium methoxide which undergoes again type of reaction, the methoxide ion attacks the carbon atom through the back side and provides Inverse configuration of methoxy compound. This is shown below,
Given information:
The given compound is shown below,
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Chapter 11 Solutions
Organic Chemistry
- The reaction of butan-2-ol with concentrated aqueous HBr goes with partial racemization, giving more inversion thanretention of configuration. Propose a mechanism that accounts for racemization with excess inversion.(b) Under the same conditions, an optically active sample of trans-2-bromocyclopentanol reacts with concentrated aqueous HBr to give an optically inactive product, (racemic) trans-1,2-dibromocyclopentane. Proposea mechanism to show how this reaction goes with apparently complete retention of configuration, yet withracemization. (Hint: Draw out the mechanism of the reaction of cyclopentene with Br2 in water to give thestarting material, trans-2- bromocyclopentanol. Consider how parts of this mechanism might be involved in thereaction with HBr.)arrow_forwardExplain this observation: Ethyl 3-phenylpropanoate(C6H5CH2CH2CO2CH2CH3 ) reacts with electrophiles to afford ortho- and para-disubstituted arenes, but ethyl 3-phenylprop-2-enoate (C6H5CH=CHCO2CH2CH3) reacts with electrophiles to afford metadisubstituted arenes.arrow_forwardThe reaction of (S)-2-bromopentane with potassium cyanide to yield 2-methylpentanenitrile (2-cyanopentane) occurs via a nucleophilic substitution pathway. The reaction is 100% stereospecific.arrow_forward
- In an aqueous solution containing sodium bicarbonate, aniline reacts quickly withbromine to give 2,4,6-tribromoaniline. Nitration of aniline requires very strong conditions,however, and the yields (mostly m-nitroaniline) are poor.(a) What conditions are used for nitration, and what form of aniline is present under theseconditions?arrow_forwardThe following questions concern ethyl (2-oxocyclohexane)carboxylate.(a) Write a chemical equation showing how you could prepare ethyl (2-oxocyclohexane)-carboxylate by a Dieckmann cyclization.(b) Write a chemical equation showing how you could prepare ethyl (2-oxocyclohexane)-carboxylate by acylation of a ketone.(c) Write structural formulas for the two most stable enol forms of ethyl (2-oxocyclohexane)carboxylate.(d) Write the three most stable resonance contributors to the most stable enolate derived from ethyl (2-oxocyclohexane)carboxylate.(e) Show how you could use ethyl (2-oxocyclohexane)carboxylate to prepare 2-methylcyclohexanone.(f) Give the structure of the product formed on treatment of ethyl (2-oxocyclohexane)-carboxylate with acrolein (H2C=CHCH=O) in ethanol in the presence of sodium ethoxidearrow_forwardThe treatment of (CH3)2C=CHCH2Br with H2O forms B (molecular formula C5H10O) as one of the products. Determine the structure of B from its 1H NMR and IR spectra.arrow_forward
- Propose mechanisms and draw reaction-energy diagrams for the following reactions. Pay particular attention to the structures of any transition states and intermediates. Compare the reaction-energy diagrams for the two reactions, and explainthe differences.(a) 2-Bromo-2-methylbutane reacts with sodium methoxide in methanol to give 2-methylbut-2-ene (among other products).(b) 2-Bromo-2-methylbutane reacts in boiling methanol to give 2-methylbut-2-ene (among other products)arrow_forwardH 9. (a) Optically active 2-bromobutane undergoes racemization on treatment with a solution of KBr. Give a mechanism for this racemization. (b) In contrast, optically active butan-2-ol does not racemize on treatment with a solution of KOH. Explain why a reaction like that in part (a) does not occur. (c) Optically active butan-2-ol racemizes in dilute acid. Propose a mechanism for this racemization.arrow_forwardCompounds X and Y are both C7H15Cl products formed in the radical chlorination of 2,4-dimethylpentane. Base-promoted E2 elimination of X and Y gives, in each case, a single C7H₁4 alkene. Both X and Y undergo an SN2 reaction with sodium iodide in acetone solution to give C7H15l products; in this reaction Y reacts faster than X. What is the structure of X? • Do not use stereobonds in your answer. • In cases where there is more than one possible structure for each molecule, just give one for each. . Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. Separate structures with + signs from the drop-down menu. наarrow_forward
- Give the products for each of the following reactions. (a) (b) (c) + H₂cod OCH3 о || -COCH 3arrow_forwardThe reaction of 3,4-dimethyl-3-hexanol (3,4-dimethylhexan-3-ol) with HBr generates compound A as the major product. Treatment of compound A with a strong base gives two isomers of compound B as the major product, along with one isomer of compound C and one isomer of compound D as minor products, all of which have one double-bond equivalent. Identify compounds A, B, C, and D and give their names. By what mechanism does the reaction of 3,4-dimethyl-3-hexanol with HBr occur? By what mechanism does the reaction of A with strong base to form B occur? Propose reaction conditions for an alternative, one-step method for converting 3,4-dimethyl-3-hexanol directly to compound B.arrow_forwardThe reaction of (S)-2-bromopentane with potassium cyanide to yield 2-methylpentanenitrile (2-cyanopentane) occurs via a nucleophilic substitution pathway. The reaction is 100% stereospecific. Please explain in complete words what this observation tells you about the mechanism of the reaction.arrow_forward