Stereochemistry Question

[dentistin2011]

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how do I distinguish identical compounds?

 

[Dotoday]

You mean, how to do (D and L )(R and S) configuration? It is in any orgo book. I mean it is freely available on line. There nothing too difficult. Try this link http://www.answers.com/stereochemistry?cat=health
This should help you. Good luck.

 

[busupshot83]

how do I distinguish identical compounds?

Here's how you assign absolute configuration to a compound:

1) Draw molecule as a Fischer Projection. To do this, "look" at the molecule from a perspective that makes the wedges on the horizon. Here's a picture depicting what I'm talking about: http://upload.wikimedia.org/wikipedia/commons/e/e3/Fischer_Projection2.png

2) Assign priorities from 1 to 4 (1 being highest priority) to each substituent based on these atomic weight. Here's a link with a more in-depth review of assigning priorities:
http://en.wikibooks.org/wiki/Organic_Chemistry/Chirality/R-S_notational_system

3) hold the bottom substituent of the Fischer Projection still, and rotated the rest of the substituents so that the one with the lowest priority (the one you labeled 4) is at the top position.

4) Draw a circular line from subsitutent with priority 1 --> subsitutent with priority 2 --> substituent with priority 3. If this line is counterclockwise, the chiral center gets a "S" absolute configuration. If this line is clockwise, the chiral center getrs a "R" absolute configuration.

 

[dentistin2011]

Does anyone have 'Paula Yurkanis Bruice Organic Chemistry 4th edition'?
I have questions on Problems # 57 (g,h,o,p) on Page 233.
Why are they identical?

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