course reader page 96 neo and tert

[terdaf]

Can someone explain why we use -tert- instead of -neo- in the example for 2 substituents on ring on page 96 of course reader? Arent three CH3s attached to a C described by the "neo" structure?

[Fengting Liang 1F]

I think it's because there has to be 4 C-C connections on the attached group to be able to use the prefix "neo". So if you ignore the hexane and the line connecting the butyl to the hexane, there are only 3 C-C connections (which is why you use the prefix for 3, "tert"), because butyl only has 4 carbons.

[samuelkharpatin2b]

You use the prefix neo- when a substitutent has AT LEAST 5 carbons. If the substitutent is composed of fewer than 5 carbons, you cannot use the prefix neo-. Tert-butyl for instance looks similar to neo-(something) in drawings, but due to the number of carbons, you wouldn't use neo-.

[Eric_pierce_3E]

This was a helpful thread! Thank you!