Wednesday, April 28, 2010

Organic chemistry questions...any advice will be greatly appreciated!!?

Can anyone help me draw these 2 compounds..





2z,4z hexadiene and 2z4e hexadiene





thank you for your help!Organic chemistry questions...any advice will be greatly appreciated!!?
It would be easier to show if we could draw on here haha!





Anyway, you start out by recognizing that the carbon chain is hexane (6 carbons). Second, you recognize that the ';diene'; tells you that there are two double bonds and finally you notice that the numbers and letters in front of the name tell you where the double bonds are and the stereochemistry. (z) means that the double bond is ';cis'; while (e) means that the double bond is ';trans. So, for 2z,4z, hexadiene, you would draw a hexane chain with double bonds between carbons 2-3, and carbons 4-5 drawing both of these double bonds ';cis';. The second compound would be drawn the same except the double bond between carbons 4-5 will be drawn trans. Draw it out and you'll see it's pretty simple!Organic chemistry questions...any advice will be greatly appreciated!!?
The only difference between the two compounds is that in the first one, the ';z'; notation indicates that the high priority groups at position two's double bond termini are ';zusammen'; or on the same side of the double bond. (i.e. ';cis'; to each other).





The ';e'; notation tells us that the high priority groups at the fourth position's double bond termini are ';entgegen,'; or in opposing positions relative the double bonded carbons they have between them. (i.e. ';trans'; to each other.)





So, the 2z,4z hexadiene would look like this, roughly:





\__/'''''''''\.





While the 2z,4e hexadiene would look like this, roughly:


~~~__/


\__/





*All horizontal lines are double, pi bonds between carbons at 2 and 4 (with those at 3 and 5, respectively)


*Ignore the little squiggles, they are just there to hold the spaces - only pay attention to the lines.





Er... just go to the link and open the powerpoint.








Best of luck!
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