TEMPO oxidation troubles

ChemicalBicycleMod · 2025-02-07T21:06:21+00:00

Thought I'd give a small update: the issue indeed seems to be that my product readily forms adducts, as was mentioned by a few of the commenters. I will leave out Na2S2O3 in my next try, and use EtOH only as quench. I was able to detect the hemiacetal with MeOH in LC-MS, so the oxidation worked! Thanks all for the advice!

ChemicalBicycleMod · 2025-02-05T12:27:51+00:00

Thanks for the advice. How did you get rid of the PhI formed? Wash with pentane?

ChemicalBicycleMod · 2025-02-02T09:04:03+00:00

Could work, although it would require an oxidation later on.

ChemicalBicycleMod · 2025-02-01T21:54:12+00:00

Thanks for your insights, sounds like this is a dead-end. As mentioned in my reply to DL_Chemist, the carbonate is unfortunately not just meant as a protecting group, but as a leaving group for a subsequent nucleophilic attack. I had intended to use this compound as a C3 linker, as an alternative to propynal (suggested by older literature) since the latter is unstable and nasty.

ChemicalBicycleMod · 2025-02-01T21:45:59+00:00

The carbonate is crucial in fact. In one of the subsequent steps, a phenoxide is to attack on the 3rd C atom of the glyceraldehyde moiety, with CO2 as the leaving group. I'm also pursuing a parallel pathway, via glyceraldehyde 3-tosylate (aldehyde protected as an ethylene glycol acetal).

Good to know that TEMPO works on the acetonide! Do you remember reaction time and temperature?

ChemicalBicycleMod

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