Question

How do we draw `cis-1-"chloro"-"2"-"pentene"`?

Answer 1

Correctly........

Explanation:

This was taken from the Sigma-Aldrich catalogue, which has always been used as a valuable reference. How would we draw it normally?

We draw a 5-carbon backbone, and in the head position we substitute the chlorine; at `C_2`, where `C_1` is attached to chlorine, we draw an olefinic bond, `HC=CH`, between `C_2` and `C_3`. The geometry around the olefin, the cis geometry, must also be introduced at this stage.