Q.20.

Question

Question: Two steps in a synthesis of the analgesic ibuprofen, the chapter-opening molecule, include a carbonyl condensation reaction, followed by an alkylation reaction. Identify intermediates A and B in the synthesis of ibuprofen.


Step-by-Step Solution

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Answer

Answer

1Step 1: Claisen Reaction

The reaction between two esters that proceeds with the formation of an enolate of one of the esters that attacks the carbonyl carbon of the other resulting in the formation of a β-keto ester is known as the Claisen reaction.

2Step 2: Claisen Reaction Mechanism

The mechanism of the Claisen reaction is provided below.


Mechanism of Claisen reaction

3Step 3: Synthesis of ibuprofen

The synthesis of ibuprofen is shown below.


Synthesis of ibuprofen