Summary: Carbocycles
Terms
Summary and Analysis
- Introduction to Cycloalkanes
- Conformational Analysis of Cycloalkanes
- Problems: Cycloalkanes
- Polycyclic Compounds
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Organic Chemistry: Carbocycles

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Conformational Analysis of Cycloalkanes

Problems: Cycloalkanes

Problem : Please draw the most stable conformations of the following molecules as 3D chair representations. When relevant, please indicate side chain conformations as well.

Solution for Problem 1 >>

Problem : The isomers of dimethylcyclohexane present an interesting opportunity to examine steric interactions in cyclic compounds. Please rationalize the following thermodynamic data by (i) drawing out both chair conformations of each compound, and (ii) indicating the presence of any unfavorable steric interactions.

Solution for Problem 2 >>

Problem : Please circle the more stable compound in each of the following pairs and give a brief rationale for your choice:

Solution for Problem 3 >>

Problem : Monosubstituted cyclohexanes always prefer to orient their substituent in an equatorial position in order to minimize 1,3-diaxial interactions. Consider the following free energy data:

Notice that there is relatively little change in going from Me to Et to I-Pr, but that there is a large increase in free energy in going to t-Bu. Draw 3D conformations of all four compounds in axial conformations (including side-chain conformations) and rationalize this trend. (Optional: What is the name given to the "extra" interaction in the t-Bu compound?)

Solution for Problem 4 >>