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Video Solution: Repeat Problem 3.40 for the stereoisomeric steroid skeleton ...

Problem

Repeat Problem 3.40 for the stereoisomeric steroid skeleton having a cis ring fusion between the rst two rings. A typical steroid skeleton is shown along with the numbering scheme used for this class of compounds. Specify in each case whether the designated substituent is axial or equatorial. 

(a) Substituent at C-1 cis to the methyl groups 

Video Transcript

So, now let's go ahead an add substituents at these locations 1, 4, 7, 11 and 12 and we're going to respect cis or trans depending on what we're told here, relative to our methyl groups here, so guys we're actually going to ignore number 1 for a second, okay? Because it gets a little bit tricky but if we look at 4 we can see that if it's going to be cis it should be going up, which means that it's going to be equatorial, right? Number 7 is also going to be, is going to be trans, so that means that it's going to be down, so that's going to be axial, 11 wants to be trans, right? So it's going to be going down, so it's going to be equatorial, number 12 is going to be cis, so it's just going to be going straight up, equatorial, and now let's actually do it number 1. So, number 1 you might be thinking, okay we've got it, if it's it it's got to go this way but look at that location, that doesn't exist, right? We either have this or we have this, an equatorial has a Z axis component, so it's not going to be going directly in the same direction as this methyl group. So, actually it's going to be this way and it's going to be axial, alright? So guys, let me know if you have any questions, if not, let's move on.

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