Concept explainers
Interpretation:
The mechanism for the epimerization of cis-declone to trans-declone, and the chair conformational structure that show trans-declone is more stable than cis-declone are to be drawn.
Concept introduction:
Keto and enol forms of carbonyl compounds are called constitutional isomers. Interconvertible keto and enol forms are called tautomers.
Racemization takes place at the
Cis–trans isomers are known as configurational isomers. If two groups are present on the same side of the carbon double bond, the isomer is a cis-isomer. If two groups are present on the opposite side of the carbon double bond, the isomer is a trans-isomer.
Epimerization is the process by which less stable epimers are converted to more stable epimers.
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EBK ORGANIC CHEMISTRY
- Give IUPAC names for the following structures. (If appropriate, specify relative stereochemistry.) (a) (b) S Sarrow_forwardIn some nucleophilic substitutions under SN1 conditions, complete racemization does not occur and a small excess of one enantiomer is present. For example, treatment of optically pure 1-bromo-1-phenylpropane with water forms 1-phenylpropan-1-ol. (a) Calculate how much of each enantiomer is present using the given optical rotation data. (b) Which product predominates—the product of inversion or the product of retention of configuration? (c) Suggest an explanation for this phenomenon.arrow_forwardplease provide reactants, and show stereochemistry where appropriatearrow_forward
- In some nucleophilic substitutions under SN1 conditions, complete racemization does not occur and a small excess of one enantiomer ispresent. For example, treatment of optically pure 1-bromo-1phenylpropane with water forms 1-phenylpropan-1-ol. (a) Calculate how much of each enantiomer is present using the given optical rotation data. (b) Which product predominates—the product of inversion or the product of retention of configuration? (c) Suggest an explanation for this phenomenon.arrow_forwardIn some nucleophilic substitutions under SN1 conditions, completeracemization does not occur and a small excess of one enantiomer ispresent. For example, treatment of optically pure 1-bromo-1-phenylpropane with water forms 1-phenylpropan-1-ol. (a) Calculate how much of each enantiomer is present using the given optical rotation data.(b) Which product predominates—the product of inversion or the product of retention of configuration? (c) Suggest an explanation for this phenomenon.arrow_forwardConsider the E2 elimination of Compound A, and answer the following questions: (a) Label each stereocenter in Compound A with the correct R or S configuration. (b) Draw the structures of the major product with correct stereochemistry. Assume D and H have the same reactivity.arrow_forward
- The bicyclic heterocycles quinoline and indole undergo electrophilic aromatic substitution to give the products shown. (a) Explain why electrophilic substitution occurs on the ring without the N atom for quinoline, but occurs on the ring with the N atom in indole. (b) Explain why electrophilic substitution occurs more readily at C8 than C7 in quinoline. (c) Explain whyelectrophilic substitution occurs more readily at C3 rather than C2 of indole.arrow_forwardThe bicyclic heterocycles quinoline and indole undergo electrophilic aromatic substitution to give the products shown. (a) Explain why electrophilic substitution occurs on the ring without the N atom for quinoline, but occurs on the ring with the N atom in indole. (b) Explain why electrophilic substitution occurs more readily at C8 than C7 in quinoline. (c) Explain why electrophilic substitution occurs more readily at C3 rather than C2 of indole.arrow_forwardStearolic acid, C18H32O2, yields stearic acid on catalytic hydrogenation and undergoes oxidative cleavage with ozone to yield nonanoic acid and nonanedioic acid. What is the structure of stearolic acid?arrow_forward
- Provide the IUPAC name for each of the following compounds. Pay close attention to stereochemistry. (a) (b) -NH2 (c) OH ОН NH2 NH2 НО .CI Br. NH2 O,N"arrow_forwardDraw a structural formula for the alcohol formed by treating each alkene with borane in tetrahydrofuran (THF) followed by hydrogen peroxide in aqueous sodium hydroxide, and specify stereochemistry where appropriate. (a) (d) (b) (e) (c)arrow_forward> acetone > ethane - Two molecular ions H3C-CH₂-CH₂-COR and have undergone McLafferty rearrangement and Ortho effect respectively. What are the possible fragments obtained as a result of these processes ? COOCH3 OH + -COH]: [CH₂O and Co] CO (A) (B) x] : [GH₂C (C) RH, C₂H₂ and CH₂CO: [(CH₂O), CO and CH₂OH] (D) H₂CCROH and C₂H4; [(CH₂O), CO and CH₂OH] R-CH₂-CH₂ - CH₂ - COH H₂C=CR = CROH and H₂C = CH₂ C₂H403 and CH4 P.T.O.arrow_forward
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