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Topic: Newman Projections (dealing with alcohols/ethers)  (Read 6006 times)

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Offline gradu8in2003

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Newman Projections (dealing with alcohols/ethers)
« on: February 26, 2008, 05:57:20 PM »
I'm trying to figure out which of the isomers of C4H10O has two non-superimposable staggered conformations...

I have all seven isomers (4 alcohol, 3 ether) written out, but I have no idea where to start to come up with the Newmans. I've done a little research online and found the basic Newman for butane, but I don't know how this would be edited to go from an alkene to an alcohol or ether.

If someone has an example of a more complicated Newman projection (certainly not asking for one of these, just anything similar that I could look at) I would appreciate it.... or any help at seeing where to start...

Thanks!

Offline azmanam

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Re: Newman Projections (dealing with alcohols/ethers)
« Reply #1 on: February 26, 2008, 08:10:23 PM »
1) Draw out the compound in the straight chain form with the longest linear chain all in the plane.
2) Choose the bond you want to look down.
3) draw the basic outline of a staggered Newman projection with one line going straight up on one side and one line going straight down on the other (which goes in front is arbitrary, but learning which maps better onto your straight chain molecule - one form will be easier)
4) one side of your longest linear chain goes on one straight line, the other side of the longest linear goes on the other straight line.
5) place in and out of plane substituents in corresponding spots on Newman projection.  See example.
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Offline azmanam

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Re: Newman Projections (dealing with alcohols/ethers)
« Reply #2 on: February 26, 2008, 08:10:23 PM »
Edit by azmanam:

*duplicate post deleted*

I think it was the size of the .tif.  Sorry guys...

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Offline azmanam

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Re: Newman Projections (dealing with alcohols/ethers)
« Reply #3 on: February 26, 2008, 08:17:21 PM »
btw, do the instructions for your particular problem demand you compare staggered Newman conformations?  There are other ways to decide if isomers are constitutional isomers, diasereomers, enantiomers or identical/meso...
Knowing why you got a question wrong is better than knowing that you got a question right.

Offline gradu8in2003

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Re: Newman Projections (dealing with alcohols/ethers)
« Reply #4 on: February 26, 2008, 11:15:06 PM »
Yes, we must use the Newmans. Thanks so much for that example. It is starting to clear things up already! :)

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