Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: webguy54 on March 20, 2008, 06:48:51 PM
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Are Wittig reactions and the Horner-Emmons-Wadsworth modification of the Wittig reactions classified as substition reactions?
The sections containing both reactions directly follow a section entitled "Addition of Carbon Nucleophiles." I believe they're substition reactions, but I would like to make sure since the chapter text doesn't state that it's speaking about anything else but addition reactions of aldehydes and ketones.
Thank you for your help.
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I would not consider it a 'substitution reaction'. The first step is carbonyl addition, but I would classify the net reaction as an 'olefination reaction' - one that introduces an alkene.
The preparation of the ylide begins with a substitution reaction, but I would not consider the Wittig or HWE as substitution reactions.
see here:
http://www.mnstate.edu/jasperse/Chem365/Wittig.doc.pdf
http://en.wikipedia.org/wiki/Wittig_reaction
http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch17/ch17-3-2-3.html