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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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 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_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 whyelectrophilic substitution occurs more readily at C3 rather than C2 of indole.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 why electrophilic substitution occurs more readily at C3 rather than C2 of indole.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_forwardGive reasons: (i) C—Cl bond length in chlorobenzene is shorter than C—Cl bond length in CH3—Cl.(ii) The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.(iii) SN1 reactions are accompanied by racemization in optically active alkyl halidesarrow_forward
- 19.24 Cyclohexene can be converted to 1-cyclopentenecarbaldehyde by the following series of reactions. O Os04 H₂O₂ C6H12O₂ HIO, CH1002 base CHO 1-Cyclopentenecarbaldehyde Propose a structural formula for each intermediate compound.arrow_forwardG.24.arrow_forward4.35 Formulate the reaction of cyclohexene with (i) Br2 and (ii) meta-chloro- peroxybenzoic acid followed by H30+. Show the reaction intermediates and the final products with correct cis or trans stereochemistry. 4.36 What products would you expect to obtain from reaction of cyclohexa- 1,3-diene with each of the following? (a) 1 mol Br2 in CH2C12 (c) 1 mol DCl (D = deuterium, ²H) (b) 1 mol HCl (d) 2 mol H2 over a Pd catalyst 4.37 Predict the products of the following reactions on hex-1-yne: (a) 1 equiv HBr ? (b) 1 equiv Cl2 ? (c) H2, Lindlar catalystarrow_forward
- Consider the tetracyclic compound with rings labeled A–D. (a) Which ring is the most reactive in electrophilic aromatic substitution? (b) Which ring is the least reactive in electrophilic aromatic substitution?arrow_forwardIdentify the major product(s) of the following reactions. Include stereochemistry. (a) (b) (c) Br NaOEt NaOEt NaOEtarrow_forwardWhich of the following could be used as a solvent in the deprotonation reaction of terminal alkynes? A CH;OH (I) B CH;COOH (I) NH3 (1) D) H20 ()arrow_forward