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Organic Synthesis And Named Reactions Mock Tests

28 questions available

Organic Synthesis And Named Reactions Mock Test 1

Questions: 28

Sample Questions

GATE Chemistry
The Heck coupling reaction between bromobenzene and methyl acrylate (methyl propenoate, CH₃OOC−CH=CH₂) catalysed by Pd(OAc)₂ with triphenylphosphine and a base (Et₃N) yields which major product? (Consider the regioselectivity of the migratory insertion step and the preference for forming the more stable trans (E) alkene.)
A Methyl (E)-cinnamate (methyl (E)-3-phenylprop-2-enoate)
B Methyl 3-phenylpropanoate
C Methyl (Z)-cinnamate (methyl (Z)-3-phenylprop-2-enoate)
D Methyl 2-phenylacrylate
GATE Chemistry
The Suzuki-Miyaura cross-coupling reaction between bromobenzene and phenylboronic acid in the presence of a Pd(0) catalyst and base yields which product as the major organic compound? (The reaction is typically carried out in a mixture of water and an organic solvent such as THF or dioxane with Na₂CO₃ as the base.)
A Biphenyl
B Benzophenone
C Diphenyl ether
D Benzyl alcohol
GATE Chemistry
In the retrosynthetic analysis of 1-phenylbutan-1-one (C₆H₅COCH₂CH₂CH₃, also known as butyrophenone), which of the following represents the most logical synthetic disconnection using the Friedel-Crafts acylation strategy? (Consider the directness of the approach, the regioselectivity of electrophilic aromatic substitution, and the compatibility of the reagents.)
A Disconnect between the carbonyl carbon and the α-carbon: C₆H₅CO⁺ + CH₃CH₂CH₂Cl → C₆H₅COCH₂CH₂CH₃ via Friedel-Crafts acylation with butanoyl chloride and AlCl₃
B Disconnect between the phenyl ring and the α-carbon: C₆H₅⁻ + CH₃CH₂CH₂COCl → C₆H₅COCH₂CH₂CH₃ via nucleophilic aromatic substitution
C Disconnect the phenyl ring from the carbonyl: C₆H₅Cl + CH₃CH₂CH₂CO₂H → C₆H₅COCH₂CH₂CH₃ via direct coupling
D Disconnect at the carbonyl: C₆H₅CHO + CH₃CH₂CH₂MgBr → C₆H₅COCH₂CH₂CH₃ via Grignard addition followed by oxidation
GATE Chemistry
The Heck coupling of styrene with an aryl halide Ar-X gives predominantly which product?
A Ar-CH=CH₂ (biaryl)
B Ar-CH=CH-Ar (trans-stilbene derivative)
C Ar-CH₂-CH₂-Ar
D Ar-CO-CH₃
GATE Chemistry
The Wolff-Kishner reduction converts aldehydes and ketones to alkanes using which reagent system?
A Zn(Hg) and concentrated HCl
B NH₂NH₂ and KOH (or NaOH) at high temperature
C LiAlH₄ in ether
D H₂ with Pd/C catalyst
GATE Chemistry
Which of the following compounds undergoes nucleophilic aromatic substitution (NAS, S_NAr) with sodium methoxide (NaOCH₃) in methanol at the fastest rate? (Consider the mechanism of S_NAr, which proceeds via a Meisenheimer complex intermediate. Electron-withdrawing groups, especially at ortho and para positions, stabilize the anionic intermediate and accelerate the reaction.)
A 1-chloro-2,4-dinitrobenzene
B 1-chloro-4-nitrobenzene
C Chlorobenzene
D 1-chloro-4-methylbenzene
GATE Chemistry
The Norrish Type II reaction of pentan-3-one upon irradiation with UV light gives primarily:
A Butanone and ethene
B Propanal and ethane
C Pentane and CO
D Acetone and ethylene
GATE Chemistry
The electrocyclic ring closure of (2E,4Z,6E)-octa-2,4,6-triene under thermal conditions proceeds via which stereochemical pathway, and what is the stereochemistry of the resulting cyclohexene product? (Consider the frontier molecular orbital analysis and the Woodward-Hoffmann rules for a conjugated system with 6 π electrons.)
A Conrotatory, giving a chiral product as a racemic mixture
B Disrotatory, giving a meso compound
C Conrotatory, giving a meso compound
D Disrotatory, giving a chiral product as a racemic mixture

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