Br ball & sticklabes Name the above compound, identify each substitutent as axia

Question

Br ball & sticklabes Name the above compound, identify each substitutent as axial or equatorial, and tell whether the conformation shown is the more stable or less stable form. Omit customary italics from your name. Substitutents R1 and R2 are designated in the order they appear in the IUPAC name. Axial/equatorial strain energy increments are available in the table below. 1. The IUPAC name is cis-1-bromo-4-ethylcyclohexane 2. Position of R1 axialPosition of R2 axial 3. The conformation shown is the more stable

Explanation / Answer

The IUPAC name of the above compound is trans-1-bromo-4-ethylcyclohexane. According to the image, Br group appears to be on equatorial position since it is allign in the plane and the hydrogen on C-1 carbon is above the plane therefore it is axial. (Please note that those substituents which would appear in the same plane as that of carbon would be equatorial and substituent which would be appear above or below the plane would be axial, as per the orientation that you have provided)

Now, if we look carefully at C-4 carbon then the ethyl group is in the plane so it should attain an equatorial positions and the hydrogen seems just behind the carbon (i.e., below the plane), Hence the substituent R1 which is Bromo group is on equatorial positions and the R2 substituent is also on equatorial positions.

As in chair conformation of cyclohexanol, the C-1 equatorial and C-4 equatorial are trans to each other therefore the compound should be named as trans-1-bromo-4-ethylcyclohexane.

The conformations is very stable as both the substituents are bulky and are on equatorial positions where no repulsion between the atoms of substituent and the rest of the molecule occurs.

Hence, the answers are as follows:

1. trans-1-bromo-4-ethylcyclohexane

2. Position of R1 is equatorial. Positions of R2 is also equatorial

3. The conformation is stable.

However, if you want to know the position of cis-1-bromo-4-ethylcyclohexan, then R1 would be on equatorial position and R2 would be on axial position or vice versa.

But from the image, both substituents appear to be equatorial.

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.