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
- In 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_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_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_forwardArrange the alkenes in each set in order of increasing rate of reaction with HI and explain the basis for your ranking. Draw the structural formula of the major product formed in each case.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
- Two isomers, A and B, of molecular formula C5H8 undergo catalytic hydrogenation with hydrogen gas and palladium on carbon to form the same C5H10 product. On ozonolysis followed by treatment with hydrogen peroxide (H₂O2), isomer A gave a product of molecular formula C5H8O4 that has two carboxylic acid groups in it whereas isomer B gave a product of molecular formula C5H8O3 that contains a carboxylic acid group and a ketone group. Which of the following isomeric pairs best match this data? a. Isomer A is cyclopentene and isomer is 1-pentyne O b. Isomer A is cyclopentene and isomer B is 1-methylcyclobutene c. Isomer A is cyclopentene and isomer B is 3-methylcyclobutene d. Isomer A is 1-methylcyclobutene and isomer B is 3-methylcyclobutenearrow_forwardTwo isomers, A and B, of molecular formula C5H8 undergo catalytic hydrogenation with hydrogen gas and palladium on carbon to form the same C5H10 product. On ozonolysis followed by treatment with hydrogen peroxide (H2O2), isomer A gave a product of molecular formula C5H8O4 that has two carboxylic acid groups in it whereas isomer B gave a product of molecular formula C5H8O3 that contains a carboxylic acid group and a ketone group. What is the isometric pair of A and B that corresponds?arrow_forwardTwo isomers, A and B, of molecular formula C5H8 undergo catalytic hydrogenation with hydrogen gas and palladium on carbon to form the same C5H10 product. On ozonolysis followed by treatment with hydrogen peroxide (H2O2), isomer A gave a product of molecular formula C5H8O4 that has two carboxylic acid groups in it whereas isomer B gave a product of molecular formula C5H8O3 that contains a carboxylic acid group and a ketone group. Which of the following isomeric pairs best match this data?arrow_forward
- 4.35 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_forwardRank the compounds in each group according to their reactivity towardelectrophilic substitution.(a) Chlorobenzene, o-dichlorobenzene, benzene(b) p-Bromonitrobenzene , nitrobenzene, phenol(c) Fluorobenzene, benzaldehyde, a-xylene(d) Benzonitrile, p-methylbenzonitr ile,p-methoxybenzonitrilearrow_forward[ 16 ] which of following compound(s) is/are neither acetal nor hemiacetal ? он Но Он осH-CHз CHз ОН OCH3 (1) ( II ) ( III ) (IV ) (V) (a ) compounds III and V (b) compounds Il and II (c) compounds I and V (d ) compounds IV and V (e) compounds I and IVarrow_forward