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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Aerosolid on March 25, 2017, 02:57:05 PM

Title: Selective Tosylation
Post by: Aerosolid on March 25, 2017, 02:57:05 PM

Hi! I am wondering if anyone knows why the site of triflation changes when this rxn is run in another solvent. (see the attached file for the rxn equation) :).

Title: Re: Selective Tosylation
Post by: wildfyr on March 25, 2017, 03:55:18 PM

I note that the solvent isn't the only difference. What are your first thoughts? Here we only help those who demonstrate that they have put effort into solving problems themselves.

Title: Re: Selective Tosylation
Post by: Aerosolid on March 25, 2017, 04:35:00 PM

Yea, well, in the rxn where the pyridone oxygen is tosylated a DTBMP base is applied. I imagine that the base might thoroughly deprotonate the pyridine nitrogen, thus adding a formal negative which would be delocalized onto to the oxygen. But would this make the oxygen more nucleophilic than the nitrogen?

Title: Re: Selective Tosylation
Post by: wildfyr on March 25, 2017, 10:06:54 PM

I think a phenolate is more nucleophilic than an aniline.