Can we apply E-Z nomenclature to geometrical isomers without a double bond. For example, can we use it for cis and trans isomers of 1,2-dimethylcyclohexane?

  • 2
    $\begingroup$ No, those are (R,R)/(R,S)/(S,S). $\endgroup$ – orthocresol May 28 at 6:28
  • $\begingroup$ @orthocresol: I didn't get your point. Shouldn't we use E-Z system as an alternate to cis-trans system of nomenclature when we go by the order of priority using CIP rule over R-S system which is meant for the spatial orientation about a chirality centre? $\endgroup$ – Guru Vishnu May 28 at 12:42
  • 2
    $\begingroup$ @GuruVishnu, if you think about the point you're making, and think about whether the carbons in 1,2-dimethylcyclohexane are chiral... You're smart enough to figure it out. Furthermore, the trans diastereomer has two enantiomers, so you're restricting yourself to two letters to describe three different things. Let's be very clear here: the descriptors cis and trans have basically nothing to do with the IUPAC descriptors Z and E. They just so happen to be the same thing in the special case of a 1,2-disubstituted alkene. $\endgroup$ – orthocresol May 28 at 13:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.