Question

A trisubstituted cyclohexane compound is given below in its chair conformation. Draw the corresponding planar (overhead) representation, using wedges and hashed bonds to indicate the substituent positions. To be graded properly, include the hydrogen atoms on the chirality centers (asymmetric carbons). Be sure that both wedges/hashed bonds are drawn on the outside of the ring, or else the stereochemistry may be interpreted as square planar.

Answer 1

Concepts and reason

Chirality center: An atom (usually carbon) which is bonded to four different atoms or groups is known as chiral center.

In the chair conformer, if the atoms are facing towards up, then those atoms must be placed at above the plane in cyclohexane ring structure. Similarly, if the atoms are facing towards down, then those atoms must be placed at below the plane in the cyclohexane ring structure.

Fundamentals

Cyclohexane is more stable in its chair conformation. In chair conformation of cyclohexane, two types of groups are present at each carbon atom. They are axial and equatorial groups. The six axial bonds one on each carbon, are parallel and alternate up-down.

The six equatorial bonds one on each carbon, come in three sets of two parallel ring bonds. Equatorial bonds alternate between sides around the ring.

In chair conformation, there is steric interaction developed between the axial groups at first and third positions to each other. This type of interaction is called 1,3-diaxial interaction.

The structure is as follows:

Number the ring as follows:

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The substituents are placed in cyclohexane ring as follows:

Ans:

Thus, the trisubstituted cyclohexane structure is as follows: