Question

For the substituted cyclohexane compound given below, highlight the groups – by clicking on atoms – that will sterically interact with the methyl group in a 1,3-diaxial fashion.

Answer 1

Answer:

            In given structure of substituted cyclohexane select the "Bromine" atom as the answer.

Explanation:

1,3-Diaxial Interactions:

                                     As cleared from name, this type of interactions are found in cyclic alkanes in which one group present at position 1 (assumed number) experiences steric hindrance due to another group present at position 3.

                                  Also, it is necessary that both the groups must be occupying either axial or equatorial positions respectively. For example, in given structure the methyl group at position 1 is at axial position and another bulky group which should interact with this methyl group must occupy axial position at carbon 3 next to carbon 1. Hence, as shown in figure, the Bromine atom is present at third carbon and is at axial position too.

                                    In attached picture, the green lines indicate steric interactions between Methyl group and Bromine atoms which are involved in steric interactions in 1,3-diaxial fashion.

Answer 2

The atoms that would sterically interact with methyl group located axially are highlighted in pink color in the attached image.

Further Explanation:

The stereoisomer of a molecule that has same chemical formula and connectivity of bond but differs in the arrangement of the atoms in space is known as conformer. The rotation about the carbon-carbon single bond can lead to the formation of conformer of a molecule.

There are four conformers of cyclohexane molecule as follows:

• Chair conformation
• Boat conformation
• Twist boat conformation
• Half chair conformation

Chair conformation is considered as the best conformation of cyclohexane. The hydrogen in blue denote the axial positions and the hydrogen in pink denote equatorial positions. (Refer to the attached image)

The stable conformation is that in which the bulky groups such as hydroxyl, methyl, and nitro group occupy the equatorial positions while the relatively small groups such as hydrogen atoms occupy axial positions. The reason is that the axially placed substituents suffer more steric repulsion and that generates strain in the molecule. The strain leads to high energy and thus less stability.

While writing the chair conformation the bulkier groups are preferentially placed at equatorial positions. The conformation that has bulky group at equatorial position is more favorable than the conformation that has bulky group at axial position. The reason for the stability of the conformation is diaxial interactions.

1,3-diaxial interaction: The 1,3-diaxial interactions occur among the axial substituent present at 1 and 3 positions.

The conformation in the problem has axial substituent hydrogen and bromine at the two positions 3 and 3’ which lead to 1,3-diaxial strain in the molecule and makes it unstable. (Refer to the attached image)

Learn more:

1. Balanced chemical equation brainly.com/question/1405182

2. Oxidation and reduction reaction: brainly.com/question/2973661

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Conformation of cyclohexane  

Keywords: Cyclohexane, planar, chair conformation, axial positions, equatorial positions, steric repulsion, high energy, 1, 3-diaxial interaction, 1, 3-diaxial strain.