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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Morgrothiel on January 19, 2007, 10:59:54 AM

Title: Nucleophilic substitution
Post by: Morgrothiel on January 19, 2007, 10:59:54 AM

I dunno if this is the right place to post this, but I think so :P

I have this task in my book, and I don't know how to solve it:

Which one of these bromides can be expected to give the largest amount of substitution products when reacting with NaOH

The bromides:
(http://morgroth.net/kjemi.jpg)

I could really need an explanation :)

Thank you for all your help :)

Title: Re: Nucleophilic substitution
Post by: english on January 19, 2007, 11:32:24 AM

It definitely wouldn't be (c) because that is an aryl bromide (I'm assuming that is a bromide that is being cut off). 

Aryl halides have more electron density around the alpha carbon, that is, the electrophilic portion of the molecule to be substituted.


Is this an S_N1 or S_N2 reaction? 

You were given this information, right?

Title: Re: Nucleophilic substitution
Post by: Morgrothiel on January 20, 2007, 06:45:46 AM

I didnt get more information than I gave you. And accordig to the answer sheet the answer is supposed to be d?

Title: Re: Nucleophilic substitution
Post by: english on January 20, 2007, 07:18:46 AM

Well your base is strong, so that follows S_N2 conditions.

The nucleophile is strong enough to readily displace Br. 

Are you sure it says d)?


It looks more like a) to me. 

Title: Re: Nucleophilic substitution
Post by: Morgrothiel on January 20, 2007, 09:17:03 AM

You are right, it is a, I looked at the wrong task :P

Thanks :)

Title: Re: Nucleophilic substitution
Post by: english on January 20, 2007, 09:25:44 AM

Quote from: Morgrothiel on January 20, 2007, 09:17:03 AM

You are right, it is a, I looked at the wrong task :P

Thanks :)

You understand why I chose a) right?

The alpha carbon in d) has more hindrance as ^-OH approaches.