Problems and exercisesHaloalkanes

1. Which mechanism is it?

State which mechanism (S_N1, S_N2, E1 or E2) each description corresponds to:

1. Rate = k[RX][Nu⁻] and inversion of configuration.
2. Carbocation intermediate and racemization of the product.
3. A single transition state in which H and the leaving group are antiperiplanar.
4. The carbocation loses a proton from the adjacent carbon.

2. 2-Bromobutane

For 2-bromobutane, CH₃CHBrCH₂CH₃:

1. Is it a primary, secondary or tertiary halide?
2. What product does it give with NaCN in DMSO, and by which mechanism?
3. What is the major product with sodium ethoxide in refluxing ethanol?

3. Choose the substrate

Which compound would you choose for a fast S_N2 reaction, CH₃I or (CH₃)₃CBr? And for an S_N1 reaction?