Naming priority between double bond and functional group

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Cindy Chen_2I
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Joined: Wed Nov 18, 2015 3:00 am

Naming priority between double bond and functional group

Postby Cindy Chen_2I » Mon Feb 29, 2016 7:30 pm

Do we prioritize function groups over double bonds in naming?

Because according to question 2.40 (c) of the Intro to Organic Chem, the OH group gets the priority over the double bond. I'm not sure but I think I heard somewhere that we're supposed to prioritize the double bond?

Albert Chong_1L
Posts: 77
Joined: Fri Sep 25, 2015 3:00 am

Re: Naming priority between double bond and functional group

Postby Albert Chong_1L » Mon Feb 29, 2016 8:48 pm

I think we prioritize other functional groups over double bonds. Would be great if someone could confirm.

HoganFenster2E
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Joined: Fri Sep 25, 2015 3:00 am

Re: Naming priority between double bond and functional group

Postby HoganFenster2E » Thu Mar 03, 2016 6:01 pm

I am not sure if that is true because in this example from Kahn Academy the double bond got the priority for the lower number.
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Hayley Hammons 1L
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Re: Naming priority between double bond and functional group

Postby Hayley Hammons 1L » Fri Mar 04, 2016 1:35 pm

When the molecule consists of alkyl groups alone, the double and triple bonds take priority in numbering. When a functional group is added, such as -OH in alcohols, the carbon attached to the -OH takes priority and is numbered as the first carbon. This is due to the idea that the alcohol functional group contributes more to the unique geometry and likelihood of specific reactions than the triple and double bonds do. Functional groups, as a general rule, contribute more to the molecule's unique structure than double and triple bonds, so they take priority in numbering.

Albert Chong_1L
Posts: 77
Joined: Fri Sep 25, 2015 3:00 am

Re: Naming priority between double bond and functional group

Postby Albert Chong_1L » Mon Mar 07, 2016 9:55 pm

There is an example in the book where a double bond takes precedence over a chloro (halide) substituent...
Maybe halides are are an exception? If so, I would expect ethers to be as well...


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