Say you need to silylate something, like an alcohol or a ketone. Boy, have I got the recipe!
- Dissolve 1.25 eq dry sodium iodide in dry acetonitrile.
- Dissolve your starting material in hexanes (pentane or heptane, all good). Don’t worry if everything doesn’t dissolve properly; solubility will increase during the course of the reaction.
- Mix the two in a suitable container. I like beakers. And stir bars.
- With efficient stirring of the bi-phasic mixture (no inert gas necessary), add 1.25 eq Et3N followed by 1.25 eq TMSCl of decent quality in one squirt.
- Stir for 15 minutes at rt.
- Separate the layers. That’s right, acetonitrile and petroleum ethers do not mix at all. Phase separation is very rapid.
- The top hexane layer has your desired product, salt free and, curiously, base free. Evaporate. Done. Quantitative yield is the general rule.
- I guess you create TMSI in situ, a notoriously unstable and hence very reactive species. It would silylate Chuck Norris.
- Perfect separation without water in any of the steps is nice.
- All the crap goes into the bottom acetonitrile layer, which you can flush down with water.
- 1 gram/10 mL total solvent volume is a good rule of thumb.
- This reaction is fast! It is typically complete before your first GCMS or LCMS is done.
- If there ever was a lit ref for this, I haven’t seen it in many years. Sorry. Anyone?
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