Question

Plan a two-stage synthesis to prepare 12.75 g of ester C (CH3CHCH3COOCH3) starting from 2-methylpropanal, (CH3)2CHCHO. Assume the overall percentage yield of ester C from 2-methylpropanal is 40%.

In your answer include the mass of 2-methylpropanal required, reagents, conditions and equations where appropriate.

Purification details are not required.

Answer 1

To prepare ester C from 2-methylpropanal, a two-stage synthesis is required. The first stage involves converting 2-methylpropanal to (4R,5R)-4,5-O-isopropylidene-2-cyclopentenone. The second stage involves using the crude product from the first stage in the synthesis of ester C.

Step-by-step explanation:

To prepare 12.75 g of ester C (CH3CHCH3COOCH3) from 2-methylpropanal, you will need to follow a two-stage synthesis. To prepare ester C from 2-methylpropanal, a two-stage synthesis is required. The first stage involves converting 2-methylpropanal to (4R,5R)-4,5-O-isopropylidene-2-cyclopentenone. The second stage involves using the crude product from the first stage in the synthesis of ester C.

The first stage involves converting 2-methylpropanal to a precursor compound called (4R,5R)-4,5-O-isopropylidene-2-cyclopentenone. This is achieved by dissolving 2-methylpropanal in dry methanol and adding CeCl3.7H2O followed by NaBH4. The reaction is then extracted into ethyl acetate and the solvent is removed to obtain the crude product. In the second stage, the crude product is used without further purification in the synthesis of ester C. The exact details of this step are not provided.