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Video Solution: The following are representations of two forms of glucose. T...

Problem

The following are representations of two forms of glucose. The six-membered ring is known to exist in a chair conformation in each form. Draw clear representations of the most stable conformation of each. Are they two different conformations of the same molecule, or are they stereoisomers that cannot be interconverted by rotation about single bonds? Which substituents (if any) occupy axial sites? 

Video Transcript

So, here we've got these two compounds that look very similar, right? The only difference is that guys look right here we see that one over wedge and dash information changed, right? So that tells me that we've got one stereo, one stereocenter changing, so we have a diastereomer, okay? So let's figure out which is actually the most stable conformation, so we're going to go ahead and draw our chair conformations and then we're going to pick which one is more stable, so I'm just going to go ahead and copy this over here, save some time and now guys over here, let's say we've got our oxygen here, so we know we've got our OH coming down here, we know that this OH is also down, so it's going to be equatorial there this OH is up, so it's going to be equatorial there, this one is down equatorial then this next one is going to be up equatorial CH2, that looks pretty stable so far and so far we've got 1, 2, 3, 4 in the equatorial and only one in the axial but can we do better? let's find out. So, here actually we're already doing better, right? Because this is the only thing we've changed, so we're going to have this now in the equatorial then this is going to be equatorial, long story short everything now is equatorial, right? So this is the more stable diastereomer, right? So guys, let me know if you have any questions I hope that helps, let's move on.

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