Question

Draw one enantiomer of the major product of the following Diels- Alder reaction. (Use wedge/dash bonds to indicate the orientation of substituents in the product. Hydrogen atoms on chirality centers must be shown explicitly.)

Answer 1

Answer 2

Answer 3

Answer 4

(1E,3Z)-4-dutero-N,N-dimethylbuta-1,3-dien-1-amine reacts with (E)-methyl but-2-enoate to form the following product The reaction is as follows: Heat (E)-methyl but-2-enoate The stereochemistry of the reaction is as follows: The given diene is a trans-cis diene (i.e. stereochemistry at one double bond is E and at other double bond is S L) While writing stereochemistry for the diene the inside groups (H and D) are came towards the observer i.e. wedge bonds) in the product. The ouside groups are away from the observer(i.e hashed bonds) For dienophile (E)-methyl but-2-enoate, the right side groups(COOCH3 and H group) are towards the observer in the product (i.e wedge bond). Left side groups (H and CH3) are far away from the observer (i.e hashed bonds) CH Out side groups H3CN Inside groups CH Left side Right side groups (Away from the Observer) Observer) groups : (Towards the Out side groups

The reaction with streochemistry is as follows CH Heat CH Exo product (less stable) If the (E)-methyl but-2-enoate approach like this way then the more stable endo product is formed. CH Heat CH Endo product (more stable) The (E)-methyl but-2-enoate approaching in this way forms more stable product This is due to there is an interaction between developing pi bond and the carbonyl group So, the product is more stabilised.

Answer 5

Rotation D 4 H for cis conformation for diels alder eaction cis Conformation of aliene require Produtt