Draw the more stable chair conformer of cis-1-ethyl-2-methylcyclohexane.

Verified step by step guidance

1. Understand the structure of cyclohexane and its chair conformations. Cyclohexane can adopt a chair conformation where substituents can occupy either axial (parallel to the ring's axis) or equatorial (perpendicular to the ring's axis) positions. Equatorial positions are generally more stable due to reduced steric hindrance.
2. Identify the substituents on the cyclohexane ring. In this case, the molecule is cis-1-ethyl-2-methylcyclohexane, meaning the ethyl group and the methyl group are on the same side of the ring (both pointing either up or down).
3. Assign the substituents to the correct positions on the chair conformation. Start by placing the ethyl group at carbon-1 and the methyl group at carbon-2. Since the molecule is cis, both substituents must be on the same side of the ring (either both axial or both equatorial).
4. Evaluate the stability of the two possible chair conformations. Place the larger substituent (ethyl group) in the equatorial position to minimize steric hindrance. This means the methyl group will also need to be equatorial in the same conformation to maintain the cis relationship.
5. Draw the final chair conformation with the ethyl group and methyl group both in equatorial positions. This is the more stable chair conformer of cis-1-ethyl-2-methylcyclohexane.

Key Concepts

Chair Conformation

Chair conformation is the most stable three-dimensional arrangement of cyclohexane rings, minimizing steric strain and torsional strain. In this conformation, the carbon atoms are arranged in a staggered manner, allowing for optimal bond angles and reducing the repulsion between adjacent substituents. Understanding chair conformations is crucial for predicting the stability of substituted cyclohexanes.

Cis and Trans Isomerism

Cis and trans isomerism refers to the spatial arrangement of substituents around a cyclohexane ring. In cis isomers, substituents are on the same side of the ring, while in trans isomers, they are on opposite sides. This distinction affects the steric interactions and overall stability of the molecule, making it essential to identify the correct isomer when drawing conformers.

Substituent Positioning

The positioning of substituents in chair conformations significantly influences the stability of cyclohexane derivatives. Substituents can occupy axial (up or down) or equatorial (outward) positions, with equatorial positions generally being more stable due to reduced steric hindrance. For cis-1-ethyl-2-methylcyclohexane, placing the larger substituent in the equatorial position is key to drawing the most stable conformer.