In the presence of a trace of acid, δ-hydroxyvaleric acid forms a cyclic ester (lactone).

(a) Give the structure of the lactone, called δ-valerolactone.
(b) Propose a mechanism for the formation of δ-valerolactone.

Two of the methods for converting alkyl halides to carboxylic acids are covered in Sections 20-8B and 20-8C. One is formation of a Grignard reagent followed by addition of carbon dioxide and then dilute acid. The other is substitution by cyanide ion, followed by hydrolysis of the resulting nitrile. For each of the following conversions, decide whether either or both of these methods would work, and explain why. Show the reactions you would use.

(a)

(b)

Peroxyacetic acid (bp = 105 °C) has a lower boiling point than acetic acid (bp = 118 °C), even though peroxyacetic acid has a higher molecular weight. Explain why peroxyacetic acid is more volatile than acetic acid.

The following NMR spectra correspond to compound of formula (C) C₆H₁₀O₂. Propose structure, and show how it is consistent with the observed absorptions.

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Show how you would accomplish the following multistep syntheses. You may use any additional reagents and solvents you need.

(f)

Two of the methods for converting alkyl halides to carboxylic acids are covered in Sections 20-8B and 20-8C. One is formation of a Grignard reagent followed by addition of carbon dioxide and then dilute acid. The other is substitution by cyanide ion, followed by hydrolysis of the resulting nitrile. For each of the following conversions, decide whether either or both of these methods would work, and explain why. Show the reactions you would use.

(e)

(f)

The following NMR spectra correspond to compound of formula (A) C₉H₁₀O₂. Propose structure, and show how it is consistent with the observed absorptions.

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