Is it possible to have 3-Chlorosuccinic acid?

Question

I have been asked to draw the structure for 3-Chlorosuccinic acid, however I realized there can only be 2-cholorosuccinic acid. Is this a typo, and if not, what will the structure of 3-chlorosuccinic look like?

Answer 1

Hehe, good catch! You are correct -- moving the -Cl substituent from the second carbon to the third carbon in the chain merely requires you to count from the other end, so you still have 2-chloro. 3-Chlorosuccinic acid would be an incorrect IUPAC name. The only way you could possibly have a 3-chloro substituent on succinic acid would be if there were some other substituent on the other carbon, which "demanded" the lower number (that is, either a higher "priority" substituent like -OH, or one which comes first alphabetically, like -Br).