For those of you who have the newest Destroyer edition, the question is Q84 in organic section. I hate cyclohexanes and I am having a very hard time understanding how to convert cyclohexane into the chair conformer to figure out which will undergo E2 fastest. I would very much appreciate your help. Please SOS...😕😕
Please help with Destroyer Question
- Thread starter Klumzy
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Check this short article out. It helped me tremendously with drawing different conformations of cyclohexane:
http://pages.towson.edu/jdiscord/WWW/331_problem_sets/Chapter1-4/cyclohexane.pdf
Look at the flat dash-wedge diagram. Then draw the chair and visualize the pair (or more) of subsitutents.
1,2 axial = 1,2 equatorial = trans
1,3 axial = 1,3 equatorial = cis
1,4 axial = 1,4 equatorial = trans
1,5 axial = 1,5 equatorial = cis
1,6 axial = 1,6 equatorial = trans
conversely, if one of the substituents is "flipped" to the other position, so does the conformation.
1 axial, 2 equatorial = 1 equatorial, 2 axial = cis
1 axial, 3 equatorial = trans
1 axial, 4 equatorial = cis
1 axial, 5 equatorial = trans
1 axial, 6 equatorial = cis
It's pretty convenient once you look at the big picture. My starting point is: 1,2 axial is obviously trans because the point opposite directions. Each additional carbon away flips the cis/trans conformation, each axial-equatorial difference flips the cis/trans conformation.
So a 1,3 cis cyclohexane has to be both axial or both equatorial, whereas a 1,4 cis cyclohexane has to have one axial and one equatorial substituent, but a 1,4 trans cyclohexane again has both axial or both equatorial substituents.
1,2 axial = 1,2 equatorial = trans
1,3 axial = 1,3 equatorial = cis
1,4 axial = 1,4 equatorial = trans
1,5 axial = 1,5 equatorial = cis
1,6 axial = 1,6 equatorial = trans
conversely, if one of the substituents is "flipped" to the other position, so does the conformation.
1 axial, 2 equatorial = 1 equatorial, 2 axial = cis
1 axial, 3 equatorial = trans
1 axial, 4 equatorial = cis
1 axial, 5 equatorial = trans
1 axial, 6 equatorial = cis
It's pretty convenient once you look at the big picture. My starting point is: 1,2 axial is obviously trans because the point opposite directions. Each additional carbon away flips the cis/trans conformation, each axial-equatorial difference flips the cis/trans conformation.
So a 1,3 cis cyclohexane has to be both axial or both equatorial, whereas a 1,4 cis cyclohexane has to have one axial and one equatorial substituent, but a 1,4 trans cyclohexane again has both axial or both equatorial substituents.
