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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Arun86 on October 22, 2013, 09:16:02 AM

Title: Poor tosylation yield
Post by: Arun86 on October 22, 2013, 09:16:02 AM

I am running a reaction of Tmob-Teg-OH . Tmob being the protecting group . I want to convert the OH to Ts but am having problems . Any suggestions on improving the yield of the Tosylation? Currently am at 35%. The reaction is carried out under R.T . I am using 2N NaOH as my base and THF as my solvent. I have tried gently heating the rxn to 50C and it doesn't seem to be helping and any higher temperature leads to product breakdown.

Title: Re: Poor tosylation yield
Post by: Babcock_Hall on October 22, 2013, 09:22:56 AM

On another thread, one commenter mentioned using pyridine (IIRC it is both a base and a catalyst), and triethylamine is a possibility for a non-nucleophilic base.  I seem to recall that DMAP is a good catalyst for this kind of reaction, but I don't have a reference handy.

Title: Re: Poor tosylation yield
Post by: 408 on December 03, 2013, 10:52:42 PM

Why are you using a nucleophillic base for a tosylation of an alcohol?  Seems like a quick route to tosylic acid.
DMF solvent, triethyl amine, your compound, and tosyl chloride.  Works on most things for me.