I have protected hydroxyl with TBDMS-Cl and tried purifying it with flash column chromatography but I see starting material after elution. This means TBDMS cleavage. Could somebody suggest how to purify it?
TBDMS protected compounds are usually purified by flash chromatography as you did. (I have performed several myself)
Does your hydroxyl presents any particularities justifying it could cleave this easily?
Otherwise it is more probable that you achieved only low conversion. What was your reaction conditions? Did you do an NMR on the crude?
Best regards,
XG
I used Room temp with stirring in DCM and imidazole. Yes the conversion was low. Theoretically it shouldn't cleave this easily. I tried eluting with 2:3 E.A./Hex hoping to separate the product, increase it to 1:1 E.A/ Hex and elute starting material. But Starting elutes with product. So the result is confusing. I was thinking the cleavage possibility.
No NMR unless I separate them.
Seems good for the conditions. In similar conditions I had to wait 24 to 36h before complete conversion (on an allylic alcohol). Did you followed your reaction by TLC?
If TBDMSCl really doesn't work, there is still TBDMSOTf which is a lot more reactive! But also more expensive...
Good luck.
Best regards,
XG
- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Atmosphere
- Air