Question

The product ’P’ in the above reaction is:

• A. \(Ph CH=CHCH_2COOH\)
• B.
• C.
• D.

Answer 1

The Correct Option is B

This reaction demonstrates a Wittig reaction, a process in organic chemistry transforming a carbonyl group (aldehyde or ketone) into an alkene using a phosphonium ylide. Let's examine the reactants and predict the product.

The reactants are:

1. A stabilized phosphonium ylide generated from \(PhCH_2P^+Ph_3 Br^-\) after base treatment.

2. 4-oxo-pentanoic acid.

The Wittig reaction mechanism involves:

The ylide attacks the carbonyl carbon of the 4-oxo-pentanoic acid, forming a betaine intermediate. This intermediate then cyclizes to an oxaphosphetane, which subsequently breaks down into the alkene and triphenylphosphine oxide. The critical step is determining the resulting alkene's structure.

The ylide \(Ph-CH=P(Ph)_3\) will react with the ketone group of the 4-oxo-pentanoic acid. The new double bond will form between the carbonyl carbon and the carbon bonded to the phenyl group in the ylide. Consequently, the product will have the following structure:

The correct product 'P' is: