Neo vs. tert

[Casey Collet 1I]

For problem number 1.17, would it be wrong to use the common name "neo" instead of using "tert"? Would one be preferred over the other or does the common name neo not even work for this example?

[Chem_Mod]

For problem number 1.17, would it be wrong to use the common name "neo" instead of using "tert"? Would one be preferred over the other or does the common name neo not even work for this example?

Neo only applies to alkyl substituents with 5 or more carbons. The neo prefix signifies a quaternary carbon which cannot exist in a butyl substituent. The Tert prefix signifies that the butyl group has a tertiary carbon.

[martha-1I]

Since Neo only applies to alkyl substituents, would it be incorrect to name this substituent neopentane since the substituent has 5 carbons in it?

[Chem_Mod]

The substituent is a tert-butyl group. It only has 4 carbons.

[martha-1I]

Oh yes! I was taking into account the carbon that was connecting it to the ring, which is not the right way to count the carbons on the substituent . Thank you for the clarification.

[Chem_Mod]

Oh yes! I was taking into account the carbon that was connecting it to the ring, which is not the right way to count the carbons on the substituent . Thank you for the clarification.

Correct! Be careful not to include carbons from you parent chain in your substituents when naming compounds.

[sandyh9711]

If neo- is only for substituents with 5 carbons or more, are there any similar rules for iso-?

Ex. 1.16: the answer is 2-isopropyl-1,1-dimethylcyclopentane. Can the iso- become sec-?