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Chair Conformation Problem

I am very confused on a few things regarding chair conformation (mainly in regards to hoe axial vs. equatorial positioning affects the structure). I guess what I am looking for is a general tutorial of how quite a few things work.

I have encountered quite a few questions on homework assignments that require knowledge of the following:

1) Knowing what the highest and lowest chair conformations would be when creating a chair conformation structure from a lewis structure/equation (most problems have a combination of many different side groups, like trans-1-bromo-2-isopropylcyclohexane)

2) Finding the lowest/highest energy structure while keeping stereochemistry R or S in mind (like (2R,3R)-2-bromo-3-phenylpentane)

3) Determining whether a substituent is in equatorial or axial position when the structure is NOT in the chair conformation (see attachment)

4) Lastly, in reactions like (E2) elimination, how do I know which carbon to form the double bond between when the carbon attached to the leaving group is attacked to more than one other carbon. I know this has something to do with the positioning, but am not sure why.

I know it is a lot of question, but this is a huge component of my upcoming organic chemistry exam. I understand most of it, but this plays such an important role in my ability to answer the questions correctly and efficiently.
I have attached two practice problems (as noted in #3) and was wondering if these could be used as an example of how to do what I asked in #3.


Solution Summary

This solution assists with the chair conformation problem.