Question

CC(C)(O)CC Oblivon Propose a synthesis for this compound starting with a… # Following is the structural formula of the tranquilizer meparfynol (Oblivon). C#CC(C)(O)CC Oblivon Propose a synthesis for this compound starting with acetylene and a ketone. (Notice the \(-y n\) - and \(-o l\) in the chemical name of this compound, indicating that it contains alkyne and hydroxyl functional groups.)

Short answer

Answer: The final synthetic pathway for the synthesis of Oblivon is: Acetylene → Propionaldehyde → 4-hydroxy-3-methyl-2-butenal → Oblivon.

Step-by-step solution

Analyze the target molecule and choose an appropriate ketone

We are given the structure of Oblivon as C#CC(C)(O)CC. Two functional groups are present: an alkyne (C≡C) and a hydroxyl group (C-OH) bonded to a tertiary carbon. Given that we start with acetylene (C≡C), we can extend it with carbon atoms and bond the hydroxyl group to form the target molecule. A suitable ketone choice can be acetone (CH3COCH3).

Perform hydroboration-oxidation on acetylene

We first need to transform acetylene into a terminal aldehyde. This can be achieved through hydroboration-oxidation. Acetylene reacts with diborane (B2H6), resulting in a vinylborane intermediate. Then, treating it with hydrogen peroxide (H2O2) in basic conditions (NaOH), we obtain terminal aldehyde, propionaldehyde (CH3CH2CHO).

Reaction of propionaldehyde with acetone

Next, we will react propionaldehyde with acetone. This reaction can be done using an aldol condensation, in which the alpha carbon of the acetone reacts with the carbonyl group of propionaldehyde, resulting in a β-hydroxy carbonyl compound with a carbon-carbon bond formed between the two molecules. In mildly basic conditions (NaOH), aldol condensation occurs to form the product 4-hydroxy-3-methyl-2-butenal.

Convert the carbonyl group to alcohol

In order to synthesize Oblivon, we need to convert the aldehyde (carbonyl) functional group in 4-hydroxy-3-methyl-2-butenal into a tertiary alcohol. To achieve this, we can carry out a Grignard reaction. First, methylmagnesium bromide (CH3MgBr) is prepared by reacting magnesium metal with methyl bromide. Then, the Grignard reagent reacts with 4-hydroxy-3-methyl-2-butenal, adding a methyl group to the carbonyl carbon and forming the desired tertiary alcohol.

Verification of the obtained product

After the Grignard reaction, the synthesis of Oblivon (meparfynol) is complete. The product has an alkyne functional group, a hydroxyl group bonded to a tertiary carbon, and the required carbon skeleton, C(CC)(O)CC, matching the given structure. The final synthetic pathway is: Acetylene → Propionaldehyde → 4-hydroxy-3-methyl-2-butenal → Oblivon.