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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Reddart on May 17, 2018, 03:57:01 PM

Title: ethynyltrimethylsilyl stable to Hartwig (NaOtBu)?
Post by: Reddart on May 17, 2018, 03:57:01 PM

I am thinking about coupling a secondary amine with (bromophenylethynyl)trimethylsilane using Pd2(dba)3,(tBu)3P, NaOtBu,toluene, but I'm not sure if the TMS will be stable enough. Should I be worried?

Title: Re: ethynyltrimethylsilyl stable to Hartwig (NaOtBu)?
Post by: wildfyr on May 17, 2018, 04:32:49 PM

Yes I think you should be worried. TMS groups are curiously similar to protons in behavior. I know there are two typical TMS-alkyne deprotection techniques: a fluoride source like TBAF or K₂CO₃ in methanol which will produce low amounts to MeO^- to deprotect the alkyne. I could not find an example on sicifinder of tert butoxide being used around a phenylethynyl trimethylsilane. Its worth a small scale hail mary attempt though since t-butoxide is pretty different from methoxide.

Title: Re: ethynyltrimethylsilyl stable to Hartwig (NaOtBu)?
Post by: Reddart on May 17, 2018, 08:07:20 PM

Im thinking that maybe I can get away with it since the reaction is in toluene, and the reaction generally has been reported to go at ambient temperatures. I'll give it a try and report what happens.

Title: Re: ethynyltrimethylsilyl stable to Hartwig (NaOtBu)?
Post by: Reddart on May 21, 2018, 04:00:45 PM

I did find a patent with similar conditions, though of course that can be suspect.