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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: kriggy on May 24, 2015, 06:52:36 AM

Title: Se2 mechanism
Post by: kriggy on May 24, 2015, 06:52:36 AM

Hi there,
In my notes its written that in Se2 mechanism there is no inversion of configuration (ie. stays same) why is that? I was thinking that the the mechanism is that the electrophile comes from the other side of the leaving group just like in Sn2. Is my understanding wrong?

Title: Re: Se2 mechanism
Post by: TheUnassuming on May 25, 2015, 02:48:31 PM

As I understand it, with Se2 you can have front and back attack depending on the exact reactants ect. 

http://www.scribd.com/doc/25905271/Aliphatic-Electrophilic-Substitution-Reactions#scribd

Title: Re: Se2 mechanism
Post by: kriggy on May 25, 2015, 03:30:28 PM

Thanks a lot, that picture on page 1 explains it pretty well  ;D

Title: Re: Se2 mechanism
Post by: swintarka on May 25, 2015, 04:54:07 PM

Sorry to write unasked, but is this mechanism really needed? Is't it also described in terms of nucleophilic substitution, but from a point of view of the other reagent?

Title: Re: Se2 mechanism
Post by: TheUnassuming on May 25, 2015, 06:24:39 PM

Quote from: swintarka on May 25, 2015, 04:54:07 PM

Is't it also described in terms of nucleophilic substitution, but from a point of view of the other reagent?

Se2 is distinctly different from SN2, although they look similar in a way when drawn, the electrons are behaving differently which is what allows for fun things like Se2 from the front!