91Ó°ÊÓ

The reaction of a diene with a simple alkene to form a cyclic compound using an addition reaction is known as the Diels-Alder reaction.

This reaction is a type of 4+2 cycloaddition reaction occurring at high temperatures.

Diene 2,3-dimethylbuta-1,3-diene is drawn such that the ends of its two double bonds are near the dienophile (E)-methyl but-2-enoate double bond.

Then form two single bonds between the diene and the dienophile, convert the three double bonds into single bonds, and convert the former single bond of the diene into a double bond.

The substituents on the dienophile are trans; thus, the cyclic product formed (1s,6s)-methyl 3,4,6-trimethylcyclohex-3-enecarboxylate also retain their trans relationship.

Formation of (1s,6s)-methyl 3,4,6-trimethylcyclohex-3-enecarboxylate