How many E/Z isomers are possible for 6-bromo-4-chloro-2-fluoro-8-iodo-2,4,6,8- decatetraene?

Question

Quizplus · Accepted Answer

To determine the number of E/Z isomers, we need to look at the double bonds in the molecule. There are four double bonds in the molecule and the E/Z isomers depend on the relative position of the substituents on each double bond. For each double bond, there can be two possible isomers, giving us 2^4 = 16 possible isomers. However, the molecule is symmetrical, so some of these isomers will be identical. Specifically, the two double bonds in the middle of the molecule are equivalent and so are the two double bonds on the ends. Therefore, there are only two unique possibilities for each set of equivalent double bonds (middle and ends), giving us a total of 8 unique isomers. Each of these unique isomers can have a possible E/Z configuration, hence the total number of E/Z isomers is 8 x 2 = 16.

How Many E/Z Isomers Are Possible for 6-Bromo-4-Chloro-2-Fluoro-8-Iodo-2,4,6,8- Decatetraene