Question

4. Name the following compounds and state the orientation around the double bond (cis/trans or E/Z) (10 pts)

Answer 1

• The longest chain containing the double bond is:

Double bond comes first from left side numbering so, the numbering will be like:

So, it is an 8 carbon species, so oct. 1 and 6 positions have chloro and 2 and 5 positions have methyl substituents. So, 1,6-dichloro-2,5-dimethyl prefix will be there. At C2 there is alkene so, 2-ene suffix. Again the highest priority group of C2 (chloromethyl) and highest priority group of C3 ( C4) are in opposite side. So this is E isomer. So, the name is:

(E)-1,6-dichloro-2,5-dimethyloct-2-ene.

• The longest chain containing the double bond and alcohol (functional groups) is:

но

Alcohol (prior functional group) comes first from left side numbering so, the numbering will be like:

НО.

It is a seven carbon species so sept. At C6, Cl is there so prefix is 6-chloro. At C2 ethyl is there, so prefix is 2-ethyl and for the same reason 5-methyl will also be a prefix. At C2 there is alkene so, 2-ene suffix. At C1 there is -OH so 1-ol suffix will be there. Here also the highest priority groups (hydroxymethyl and C4) are in opposite side so the configuration is 'E'.So, the name is:

(E)- 6-chloro-2-ethyl-5-methylsept-2-ene-1-ol