SolutionsPreparation
1. Choose the method
Propose a method to obtain each alcohol:
- 1-Butanol from 1-butene
- 2-Butanol from butanone
- 2-Methyl-2-butanol from acetone
- Benzyl alcohol from benzyl bromide
- Hydroboration-oxidation (BH3; then H2O2, HO−): anti-Markovnikov addition.
- Reduction with NaBH4 in methanol (or catalytic hydrogenation).
- Addition of ethylmagnesium bromide to acetone followed by acid hydrolysis.
- Substitution with potassium acetate and saponification of the ester (or direct hydrolysis, since the benzylic substrate cannot eliminate).
2. Markovnikov or anti-Markovnikov
Which alcohol is obtained from propene by acid hydration? And by hydroboration-oxidation?
Acid hydration: 2-propanol (Markovnikov, through the secondary carbocation). Hydroboration-oxidation: 1-propanol (anti-Markovnikov, without carbocations).
3. Degree of the alcohol
Which kind of alcohol is obtained when a Grignard reagent is added to formaldehyde, an aldehyde and a ketone?
Formaldehyde: primary alcohol. Aldehyde: secondary alcohol. Ketone: tertiary alcohol.