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Topic: R,S Configurations  (Read 3987 times)

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Offline smilegirl

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R,S Configurations
« on: May 15, 2008, 02:51:22 PM »
If the #1 priority group is pointed backward, does one reverse the configuration. (Even if the #4 priority group is not pointed foward)?
Thanks

Offline macman104

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Re: R,S Configurations
« Reply #1 on: May 16, 2008, 02:53:24 AM »
If the #1 priority group is pointed backward, does one reverse the configuration. (Even if the #4 priority group is not pointed foward)?
Thanks
If the #4 group is not pointed back, then you reverse it.

Offline ng

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Re: R,S Configurations
« Reply #2 on: May 16, 2008, 04:23:49 PM »
In order to read off the configuration as R or S you need to orientate the molecule so that the lowest priority group (#4) is away from you, then if #1-#2-#3 is clockwise it is R.
If you don't want to turn the molecule so that #4 is away from you and it is pointing towards you then you can read off #1-#2-#3 and if it is clockwise the centre is reversed to S.

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