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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Lynda92 on April 15, 2015, 11:06:56 AM

Title: Is this phosphonium ylide stabilised?
Post by: Lynda92 on April 15, 2015, 11:06:56 AM

I'm in doubt as to whether the phosphonium ylide attached below is classified as stabilised and therefore should give E-alkene selectivity in a Wittig reaction.

BrC1=CC(C=P(C2=CC=CC=C2)(C3=CC=CC=C3)C4=CC=CC=C4)=CC(OC)=C1OCC5=CC=CC=C5<br />


   
Title: Re: Is this phosphonium ylide stabilised?
Post by: Dan on April 15, 2015, 11:47:04 AM
Shades of grey.

My gut feeling would be to the unstabilised side, but I haven't looked it up.
Title: Re: Is this phosphonium ylide stabilised?
Post by: sjb on April 15, 2015, 12:33:35 PM
Perhaps putting the cart before the horse but why not try making it and seeing what kind of selectivity you get. May vary with the carbonyl too.