TOPIC: 5

TOPIC: 5. Nucleophilic Substitution

SUBTOPIC: 50. S_N2 Mechanism

1. Which is a good nucleophile?

A. CH₃C≡CNa

B. HBr

C. Br₂

D. BH₃

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2. In which solvent will CH₃CH₂I react most rapidly with NaCN?

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3. Write the major product(s) of the following reactions showing the correct stereochemistry. Give the absolute configuration of the starting material. Pick the correct descriptor to indicate the stereochemistry of the product.

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4. Give the major product of the following reaction.

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5. Which is the most reactive halide when treated with NaI?

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6. Write the major product(s) of the following reaction showing all stereoisomers.

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7. Write the major product(s) of the following reaction showing stereochemistry in 3-D and indicate if the product(s) are optically active or inactive.

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8. The optically active diastereomers of 3-bromo-2-butanol undergo an intramolecular S_N2 reaction to yield two different products, C₄H₈O. One diastereomer gives an optically inactive product and the other gives an optically active isomer. Draw the two diastereomers in their correct stereochemical configuration and the two products also showing stereochemistry. Indicate which product is optically active.

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9. Write another resonance structure for the following polar aprotic solvent.

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10. Write the major product(s) showing stereochemistry where necessary. All the starting materials are optically active. Indicate which products are optically active and whether the reaction is S_N2, S_N1, E2 or E1.

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11. Write the major product(s) showing stereochemistry where necessary. All the starting materials are optically active. Indicate which products are optically active and whether the reaction is S_N2, S_N1, E2 or E1.

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