Natural Science Forum / Chemistry / Organic Synthesis / April 2005

I have finished a book on alcohol oxidation a few months ago and my
mind is still fresh.

Collin?s oxidation transforms primary TMS ethers directily into
aldehydes (J.Carbohydrate Chem., 20, 31 (2001); Tetr.Lett.5161 (1999)
and Synthesis, 1012 (1987).

PDC in the presence of added TMSCl is able to transform TBS and TMS
ethers in aldehydes (Can.J.Chem., 225 (1986)

TMS and TES ethers can be transformed into aldehydes under Swern
oxidation conditions (see for example: Org.Lett.1719 (2002) and 515
(2003)).

On the other hand, because of the tendency to form a lactone, the above
procedures could fail in your molecule, although they are worth trying.

Another possibility would be to treat the lactone with one equivalent
of aqueous base, resulting in the formation of a hydroxycarboxylate
that could be oxidized on the alcohol. This has been done with RuO4
(cat. RuO2 + NaIO4) resulting in the formation of a ketoacid, starting
from a hydroxiacid with a very strong tendency to form a lactone
(Tetr.Lett.4003 (1970)). Regretably, the cited reaction involved a
secondary alcohol and in your case you would have oxidation to
carboxylic acid with RuO4. On the other hand, this technique looks
theoretically quite sound and it is worth trying using different
oxidants.

Hope it helps

Best regards.

Gabriel Tojo