R/S charilty of Cortisone

[justhanging]

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What is the charility or conformation (R/S) for the two quaternary carbons in cortisone?

Pic of cortisone
http://en.wikipedia.org/wiki/File:Cortison.svg

I see that the bottom quaternary carbon as R but BR says its S, what am I missing? The methyl is the lowest priority, then its bottom double bond chain, followed by the top right chain than the top left.

 

[zoner]

What is the charility or conformation (R/S) for the two quaternary carbons in cortisone?

Pic of cortisone
http://en.wikipedia.org/wiki/File:Cortison.svg

I see that the bottom quaternary carbon as R but BR says its S, what am I missing? The methyl is the lowest priority, then its bottom double bond chain, followed by the top right chain than the top left.

I see R also.

bottom first due to a double bonded carbon,
right second due to carbonyl carbon,
then the top left
and the methyl group having the lowest priority, but sticking out so you flip the rotation to R

The top q carbon seems to be S though

 

[justhanging]

Check out the explanation:

Corticosterone has two quaternary carbons, both with the methyl substituents directed above the plane of the rings and showing the lowest priority in the R-S sequence rules. The chirality of each carbon is S, not R, making statement I invalid

I think i messed up on the compound its actually:
http://en.wikipedia.org/wiki/File:Corticosterone-2D-skeletal.svg

It doesn't change anything on the quaternary carbon though so am still confused.

 

[SmurfinUSA]

yea me too, i see the bottom one as R, because I give the alkene 3' C is a higher priority.

 

[premedstudent55]

🙁

 

[Le Boudin]

I got both as R. What am I doing wrong?

 

[Lily20]

Any luck on this one? I'm also getting R..

 

[sazerac]

Path 1 is carbon to 2 carbons.
Path 2 is carbon to one carbon.
Path 3 is carbon to 2 carbons.
Path 4 is carbon to hydrogens.

How to settle the tie between path 1 and path 3? Path 1 goes to some oxygens off of them second carbons. Path 3 doesn't.

The correct order is path 1, path 3, path 2, path 4.