Interpretation:
The resonance structure that explains the acidity of gamma carbon hydrogen atoms of crotonaldehyde and the mechanism for the given reaction are to be written.
Concept introduction:
Electrophiles are electron deficient species that have positive or partially positive charge. Lewis acids are electrophiles that accept electron pair.
Nucleophiles are electron rich species that have negative or partially negative charge. Lewis bases are nucleophiles that donate electron pair.
Free radical is an atom, molecule, or ion that has an unpaired electron that makes it highly chemically reactive.
Substitution reaction: A reaction in which one of the hydrogen atoms of a hydrocarbon or a functional group is substituted by any other functional group is called substitution reaction.
Elimination reaction: A reaction in which two substituent groups are detached and a double bond is formed is called elimination reaction.
Addition reaction: It is the reaction in which unsaturated bonds are converted to saturated molecules by the addition of molecules.
A carbon–carbon bond formation occurs by aldol condensation reaction.
An aldol reaction takes place in a protic solvent with a base.
Aldol reaction is preferred in basic condition over acidic condition, as after the aldol condensation, acid catalysis promotes the reaction further.
An aldol reaction takes place by acid catalysis, and direct dehydration of
A
A chemical reaction that is catalyzed by a base is called base catalyzed reaction.
The dehydration of the aldol addition product leads to the formation of conjugated
As the stability of the conjugate base increases, the acidity increases.
The rules for drawing resonance structures are as:
Only nonbonding electron pairs and pi electrons can participate in conjugation in the formation of various resonating structures.
The single bonds present in the molecule do not break or form in the resonance structures.
The placement of atoms present in the molecule remains fixed.
The octet of all atoms is completely filled.
More the number of resonance structures indicate higher stability of a compound.
Want to see the full answer?
Check out a sample textbook solutionChapter 19 Solutions
Organic Chemistry
- Aldehydes and ketones react with thiols to yield thioacetals just as they react with alcohols to yield acetals. Predict the product of the following reaction, and propose a mechanism:arrow_forwardIn 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_forward(a) Draw the structures of the following compounds :(i) 4-Chloropentan-2-one (ii) p-Nitropropiophenone(b) Give tests to distinguish between the following pairs of compounds :(i) Ethanal and Propanal (ii) Phenol and Benzoic acid(iii) Benzaldehyde and Acetophenonearrow_forward
- Give reasons for the following: (i) p-nitrophenol is more acidic than p-methylphenol. (ii) Bond length of C—O bond in phenol is shorter than that in methanol. (iii) (CH3)3C—Br on reaction with sodium methoxide (Na+ _OCH3) gives alkene as the main product and not an ether.arrow_forward(c) Arrange the following compounds in order of increasing acidity, and explain the reasons for your choice of order: phenol, cyclohexanol, 2-fluorocyclohexanol, 2-fluorophenol.arrow_forward4) Aromatic compounds are among the most abundant and versatile in nature. From a synthetic point of view, these compounds, despite their stabilities, are quite useful and can undergo reactions under special conditions and by specific mechanisms, such as the Electrophilic Aromatic Substitution (SAE) and the Nucleophilic Aromatic Substitution (SNAr). Based on this, please answer the following items: (b) How would you prepare the following compounds starting from benzene? Explain the second in a different wayarrow_forward
- Dimethyl disulfide, CH,S–SCH3, found in the vaginal secretions of female hamsters, acts as a sexual attractant for the male hamster. Write an equation for its synthesis from methanethiol.arrow_forwardGive reasons: (i) Bond length of C = O in carboxylic acids is slightly larger than C = O bond length in carbonyl compounds. (ii) There are two –NH2 groups in semicarbazide. However, only one –NH2 group is involved in the formation of semicarbazones. (iii) Benzoic acid is less soluble in water than acetic acid. (iv) Formic acid is a stronger acid than acetic acid.arrow_forward(b) Propose a synthesis of (2,2-dimethylpropyl)benzene from benzene.arrow_forward
- y-Butyrolactone (C4H6O2, GBL) is a biologically inactive compound that is converted to the biologically active recreational drug GHB (Section 19.5) by a lactonase enzyme in the body. Since y-butyrolactone is more fat soluble than GHB, it is more readily absorbed by tissues and thus produces a faster onset of physiological symptoms. y-Butyrolactone shows an absorption in its IR spectrum at 1770 cm-1 and the following 1H NMR spectral data: 2.28 (multiplet, 2 H), 2.48 (triplet, 2 H), and 4.35 (triplet, 2 H) ppm. What is the structure of y-butyrolactone?arrow_forwardThe hydrocarbon fluorene was treated with potassium t-butoxide in an acid-base reaction, giving the fluorenide anion and t-butyl alcohol. (a) Which way does the equilibrium lie, and by how much? b) What is the proportion of the fluorenide anion to fluorene? (c) Why is fluorene so highly acidic, considering the pKa of an average alkane is above 50?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_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningIntroduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning