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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: xyzi on November 29, 2007, 04:24:24 PM

Title: TMSCl vs t-butyldimethylchlorosilane
Post by: xyzi on November 29, 2007, 04:24:24 PM

Would like to use TMSCl for BOC-deprotection (with PhOH) but what we have in the lab is t-butyldimethylchlorosilane, instead. Would the t-butyl vs methyl group make a big difference in the deprotection reaction? Im thinking that it would slow it down a bit, would it?


Title: Re: TMSCl vs t-butyldimethylchlorosilane
Post by: kiwi on December 01, 2007, 09:21:53 PM
no it wouldn't much, since the deprotection reaction is simply due to the presence of acid when the chlorosilane reacts with an alcohol (typically as the solvent).

TMSCl + ROH -> ROTMS + HCl
N-Boc + HCl -> free NH

one thing that would happen is your labmates will probably stop talking to you, since TBDMSCl ~ $US75/25g, while TMSCl is ~$US30/500 mL. try using acetyl chloride instead.
Title: Re: TMSCl vs t-butyldimethylchlorosilane
Post by: xyzi on December 05, 2007, 04:25:57 PM
thanks, kiwi, but tBDMSCl is what's available. will give it a shot.

my concern came from the claim of the paper that the reaction is not largely based on the formation of
HCl - J. Org. Chem.;   1993; 58(19); 5167-5175. 
Title: Re: TMSCl vs t-butyldimethylchlorosilane
Post by: Transmutation on February 28, 2008, 04:08:47 AM
Quote
one thing that would happen is your labmates will probably stop talking to you, since TBDMSCl ~ $US75/25g, while TMSCl is ~$US30/500 mL. try using acetyl chloride instead.

My goodness!  I thought it was cheap.  We have a gigantic tub of it in the lab I am in now; probably kilogram quantities.

 :o