To draw the most stable conformation of trans-1-isopropyl-3-methylcyclohexane, we need to consider the steric interactions and the positioning of the substituents on the cyclohexane ring.
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Identify the substituents: In trans-1-isopropyl-3-methylcyclohexane, the isopropyl group is at the 1-position and the methyl group at the 3-position on the cyclohexane ring. The 'trans' configuration indicates that these substituents are on opposite sides of the ring.
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Cyclohexane conformations: Cyclohexane can adopt a chair conformation, which is the most stable due to less steric strain, or a boat conformation, which is typically less stable.
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Placing substituents: To achieve the most stable conformation, it's best to place the larger isopropyl group equatorially (since it has more steric bulk) and the smaller methyl group axially. The trans nature means that if the isopropyl is equatorial at position 1, the methyl at position 3 will be axial.
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Sketch the chair conformation:
- Draw a chair conformation of cyclohexane.
- At carbon 1, place the isopropyl group in the equatorial position.
- At carbon 3, place the methyl group in the axial position.
This configuration minimizes steric hindrance and therefore is the most stable conformation for trans-1-isopropyl-3-methylcyclohexane.
Summary:
- Isopropyl - equatorial (C-1 position).
- Methyl - axial (C-3 position).
This orientation reduces 1,3-diaxial interactions and overall steric strain, resulting in the most stable conformer.