Problem Set 6 – Reactions of alcohols and ethers

1. Propose a mechanism for the transformation of nerol into a-terpineol:

2. The sex attractant of the Douglas fir tussock moth has been synthesized via the following route:

1-heptyne + LiNH₂ ® “A” (C₇H₁₁Li)

“A” + 1-chloro-3-bromopropane ® “B” (C₁₀H₁₇Cl)

“B” + i) Mg ii) n-C₁₀H₂₁CHO iii) H⁺ ® “C” (C₂₁H₄₀O)

“C” + H₂/Lindlar catalyst ® “D” (C₂₁H₄₂O)

“D” + CrO₃ ® sex attractant (C₂₁H₄₀O)

Draw the structure of the sex attractant.

3. Testosterone undergoes dehydration as shown below. Propose a mechanism.

4. Treatment of 4-hydroxycyclohexanone with 1 equivalent of CH₃MgBr gives no alcohol. Treatment with an excess of CH₃MgBr gives a good yield of 1-methyl-1,4-cyclohexanediol. Why?

5. What are the products of the reaction of ethoxycyclohexane and aqueous HI?

6. When 4-chloro-1-butanol is treated with strong base (eg NaH), tetrahydrofuran (C₄H₈O) is formed. Propose a mechanism.