Stereochemistry · Advanced
Draw (E)-3-methylpent-2-ene
Draw the skeletal structure of (E)-3-methylpent-2-ene, then check it. The checker compares the molecule you drew with the answer, so a correct structure is accepted however you draw it.
Stereochemistry is assessed: draw the configuration the name gives, with wedge and hash bonds or the right double-bond geometry.
How this exercise works
- Open the exercise in the editor and draw the structure: drag from dot to dot to draw bonds, and tap a bond or an atom to change it.
- Press Check answer. Equivalent drawings are accepted, and a mistake such as a missing carbon or a misplaced group is explained.
- Stuck? Hints reveal the structure step by step, and the worked answer explains the name.
This exercise has 3 hints and a worked answer.
How to read a name like this
A stereodescriptor in parentheses in front of the name fixes the arrangement in space: (E) or (Z) for a double bond, (R) or (S) for a stereocenter; a number in front of it, as in (2R), is the locant it refers to. Cis- and trans- describe two groups on the same side or on opposite sides.
E and Z compare the higher-priority group on each carbon of the double bond (CIP rules): on the same side is Z, on opposite sides E. R and S come from the order of the four groups on a stereocenter, seen with the lowest-priority group pointing away: clockwise is R, counterclockwise S.
Draw the structure from the rest of the name first. Then set the geometry of the double bond, or put one wedge or hash bond on each stereocenter, and check the descriptor.
Learn the naming rules
The guide Stereochemistry: E/Z and R/S explains the names in this topic, with worked examples.
More exercises: Stereochemistry: E/Z and R/S
- Draw (E)-but-2-ene
- Draw (Z)-pent-2-ene
- Draw (Z)-but-2-ene
- Draw (E)-pent-2-ene
- Draw (E)-1,2-dichloroethene
- Draw (R)-butan-2-ol
- Draw (S)-2-hydroxypropanoic acid
- Draw (R)-2-chlorobutane
- Draw (S)-butan-2-amine
- Draw (R)-3-methylhexane
- Draw (Z)-2-bromobut-2-ene
- Draw (2R,3R)-butane-2,3-diol
- Draw (Z)-but-2-enoic acid
- Draw (S)-2-aminopropanoic acid
- Draw (R)-1-phenylethan-1-ol
- Draw cis-1,2-dimethylcyclohexane
- Draw (R)-3-methylcyclohexan-1-one
Have a structure of your own?
Draw it on the free drawing page and see its name, formula and functional groups as you draw.