If I have a CIS cyclohexane (with 2 cis substituents), would that translate into a CIS chair conformation (with both substituents pointing in the same direction)?? Or are they completely unrelated?Because when I try converting cyclohexanes to chairs, I end up getting the trans conformation...The lowest energy conformation of cis-1-4-(1,1-dimethylethyl)cyclohexane is not a chair. Why?^^For the above question, the answer is because ONE of the t-butyl groups is in an axial position...BUT when I draw the cis cyclohexane and convert it to a chair, I get BOTH t-butyl groups in opposite-direction axial positions...which, I know, isn't the cis conformation.Is it not possible to convert from cyclohexanes to chairs? Like, having a cis cyclohexane DOES NOT translate into a cis chair conformation??
For your first question, you are likely drawing your chair conformer correctly, but interpreting it incorrectly. Are you equating equatorial and axial positions as trans? Cis substituents are sometimes in equatorial and axial positions - you can tell that they are cis if BOTH are the upper or lower subsituent. The substituents are trans if one is in the upper position, and one is in the lower position. I wish I could attach a picture to this answer to show you better. For your second question, you are probably drawing it incorrectly. One will be axial, and one will be equatorial. Remember to number your carbons so that you are drawing your substituent on the right one. tert-butyl groups are very bulky and will add a lot of steric hindrance to your molecule. In this case, a boat conformer will actually be more stable! Cis cyclohexanes do translate into chair conformations, but this particular molecule is more stable as a boat.
