4. Alkanes and Cycloalkanes

Which of the following pairs of compounds are $\mathrm{cis}-\mathrm{trans}$ isomers?

Identify the following alkenes as E or Z, if appropriate.

(b)

For those compounds that can exist as cis and trans isomers, draw and label the isomers.

1.

2.

Which of the following alkenes are E and which are Z?

(c)

For each of the following compounds, draw the possible geometric isomers and name each isomer:

d. 3-methyl-2,4-hexadiene

Name the following:

b.

Assign relative priorities to the groups or atoms in each of the following sets:

c. $-$CH(CH₃)₂

d. $-$CH$=$CH₂

Which of the following best describes cis-trans isomers?

Draw the structure that corresponds to the name provided.

(a) (1R,5S)-5-methylcyclohex-3-enol

Given a compound with the structure $\mathrm{CH}=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}}_2$, identify the configuration (cis or trans) around each double bond.

Draw the Z isomer of an alkene that has a CH₃ and an H on one sp² carbon and isopropyl and butyl groups on the other sp² carbon.

Some of the following examples can show geometric isomerism, and some cannot. For the ones that can, draw all the geometric isomers, and assign complete names using the E-Z system.

a. 3-bromo-2-chloropent-2-ene

b. 3-ethylhexa-2,4-diene

1. Determine which of the following compounds show cis-trans isomerism.

2. Draw and name the cis and trans (or Z and E) isomers of those that do.

e. 2,3-dimethylpent-2-ene

f. 3,4-dibromocyclopentene

Draw the isomers for the following compounds and then name each one:

a. 2-methyl-2,4-hexadiene

α-Farnesene is a dodecatetraene found in the waxy coating of apple skins. What is its systematic name? Include E and Z where necessary to indicate the configuration of the double bonds.