91Ó°ÊÓ

Question: Classify each diene as isolated or conjugated.

a.

b.

c.

d.

Question. Draw the structure consistent with each description.

a. (2E,4E)-octa-2,4-diene in the s-trans conformation

b. (3E,5Z)-nona-3,5-diene in the s-cis conformation

c. (3Z,5Z)-4,5-dimethyldeca-3,5-diene. Draw both the s-cis and s-trans conformations.

Question: Neuroprotectin D1 (NPD1) is synthesized in the body from highly unsaturated essential fatty acids. NPD1 is a potent natural anti-inflammatory agent.

a. Label each double bond as conjugated or isolated.

b. Label each double bond as E or Z.

c. For each conjugated system, label the given conformation as s-cis or s-trans.

Question: Using hybridization, predict how the bond length of the C-Cσ bond in $\mathrm{CH}≡\mathrm{C}-\mathrm{C}≡\mathrm{CH}$should compare with the C-Cσ bond in${\mathrm{CH}}_3{\mathrm{CH}}_3$and${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}}_2$.

Question: Use resonance theory explains why the labeled C-O bond lengths are equal in the acetate ion.

Question: Rank the following compounds in order of increasing stability.

a.

b.

c.

Question: Draw the products formed when each diene is treated with one equivalent of HCl.

a.

b.

c.

d.

Question: Draw a stepwise mechanism for the following reaction.

Question: Label each product in the following reaction as a 1,2-product or 1,4-product, and decide which is the kinetic product and which is the thermodynamic product.

Question: Draw the product formed when each diene and dienophile react in a Diels–Alder reaction.

a.

b.

c.