Q24E - Organic Chemistry (Mcmurry)

Question

An extremely useful diene in the synthesis of many natural products is

known as Danishefsky’s diene. This compound is useful because after

the Diels–Alder reaction it can be converted into a product that could

not be accessed by a typical Diels–Alder reaction. Show the Diels–Alder

adduct and propose a mechanism that accounts for the final products.

Step-by-Step Solution

Answer

The Diels-Alder adduct can be given as:

The mechanism of the reaction can be given as:

Diels-Alder reaction

Diels-Alder reaction constitutes the reaction in which the dienophile combines with a diene to generate a cyclic adduct. The cyclic product is created through a cyclic transition state and this reaction is termed as cycloaddition.

Proposing a mechanism for the products

The structure of the Diels-Alder adduct formed in the reaction between Danishfsky’s diene and acrolein can be given as:

Structure of the product

The mechanism that accounts for the formation of the products can be given as:

                                                  Mechanism of the reaction

The enol then leads to the final products given below.

                           Final products obtained from the enol