rxns for ester-->ketone

stratosphere · Sat Jun 04, 2005 5:35 pm

i was wondering if there are established reactions for reducing a ester to its corresponding ketone, or alternativly a dialkyl carbonate to ester to ketone

(e.g. R-0-(C=0)-R' --> R-(C=0)-R' )

bio · Working Bee

.........e.g. R-0-(C=0)-R' --> R-(C=0)-R' )...........

Take a look at the Baeyer/Villiger reaction. The ester formed from a ketone and peroxyacid is hydrolysed to give the corresponding ketone with two less carbons.

RCH=C(COCH3)R' + R"COOOH ---> RC(OCOR")R'---> R(C=O)R' + R"COOH

Is one example yet this reaction is applicable to a wide range of substrates but always starting from a ketone in the first place. Most widely used for synthesis of steroids and lactones.

Here are references for two other different reactions that are the only ones I could find. One is a ring closing to a lactone the other is ring opening. Both using some rather exotic reagents. Bu3SnOSnBu3 & Me1 , LiBr (-CO2) and SmI2. What's that?

Samarium Iodide? Geez I better run out and buy some of that shit right away! Smile

Molander, G.A,; McKie, J.A. J. Org. Chem., 1993, 58, 7216
Shibata. 1; Nishio, M.;Baba, A.; Matsuda, H. Chem. Lett., 1993, 1953

Not exactly what you are looking for I think.

stratosphere · Wed Jun 08, 2005 10:36 pm

bayer/villiger does about the opposite of what i was aiming for, it turns a ketone into an ester.

i should have made my question more specific,what i was really hoping for was a rxn that turned a lactone into a ketone possesing the same number of carbons. like lets say you had N-(2-hydroxy ethyl)-3-amino-propanoic acid (made from 3-cloro-propanoic acid and ethanolamine), easy to form lactone.
if you could get rid of the ether oxygen youd have piperadone. looking at the mechanism for bayer-villiger and running it backwards im sure some aweful reagent (like samarium and butyl tin, hell and why not chelate some Pt with a huge organic thing to Very Happy

) could be devised, but such masochistic work belongs in acedemia.

i think another way around is to form NH(CH2CH2COOH)2 form calcium salt and pyrolize, could theretically give piperidone, or one could really cut to the chase, and react PhCH2CH2NH3 with 2 equivs of 3-chloro-propanoic acid, pyrolize and be left with N-pheynethyl-piperadone, what they would want to do with that would be up to them.