What is the Difference Between Woodward and Prevost Reaction?

The Woodward and Prevost reactions are both used in the formation of vicinal diols from alkenes. However, there are key differences between the two reactions:

1. Reaction Conditions: The Woodward reaction proceeds in the presence of iodine and silver acetate, while the Prevost reaction proceeds in the presence of a silver salt of benzoic acid.
2. Reaction Mechanism: The Woodward reaction involves the addition of iodine followed by nucleophilic displacement with acetate. In contrast, the Prevost reaction involves a fast reaction between silver benzoate and iodine, producing a very reactive iodonium benzoate.
3. Products: The Woodward reaction generates syn-diols, while the Prevost reaction gives trans-diols.
4. Reactivity: The Prevost reagent is known for affecting other sensitive groups in the molecule less, making it a more versatile choice in certain situations.

In summary, the main differences between the Woodward and Prevost reactions lie in the reaction conditions, mechanism, products, and reactivity. Both reactions are valuable in the synthesis of vicinal diols from alkenes, but the choice between them depends on the specific conditions and desired outcomes in the laboratory.

Comparative Table: Woodward vs Prevost Reaction

The main difference between the Woodward and Prevost reactions lies in the reagents used and the type of diols formed. Here is a comparison table of the two reactions:

The Woodward reaction, also known as hydroxylation, is used for the synthesis of syn-diols or cis-diols from alkenes. In the presence of water, an alkene treated with iodine and silver acetate undergoes nucleophilic displacement with acetate, followed by hydrolysis of the intermediate ester to yield the required diols.

On the other hand, the Prevost reaction allows the synthesis of anti-diols from alkenes by the addition of iodine, followed by nucleophilic displacement with benzoate in the presence of benzoic acid silver salt.