July 05, 2020, 09:39:15 PM
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Topic: LiCl hydrolysis of Methyl esters  (Read 276 times)

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Offline wildfyr

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LiCl hydrolysis of Methyl esters
« on: March 25, 2020, 01:23:48 PM »
I feel like this topic comes up somewhat often here; the hydrolysis of methyl esters without using strong acids or bases. Found a nifty looking paper

https://www.tandfonline.com/doi/full/10.1080/00397910902778001?src=recsys

Microwave of methyl esters in DMF with LiCl. It says stereochem on alpha carbon is retained as well.

For some dumb reason they use NaOH and HCl in the workup after the fact, but obviously much weaker acids or bases could be used, or the carboxylate salt can be crystallized out.

Offline hollytara

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Re: LiCl hydrolysis of Methyl esters
« Reply #1 on: March 25, 2020, 03:45:25 PM »
I cant access full text..  For methyl esters - do they think this happens at the carbonyl or by SN2 at the methyl?  If the latter, would Li I be better? 

Offline wildfyr

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Re: LiCl hydrolysis of Methyl esters
« Reply #2 on: March 25, 2020, 04:23:52 PM »
I guess SN2, because methyl chloride is formed.

Offline Babcock_Hall

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Re: LiCl hydrolysis of Methyl esters
« Reply #3 on: March 25, 2020, 05:38:15 PM »
Possibly off-topic.  There is some literature from the mid 1950s in the area of phosphate esters in which alkali metal halide salts were used for monodealkylation (primarily of benzyl esters IIRC).  Some of the work came out of Alexander Todd's laboratory.  Unfortunately, I don't have any links, but I might still have a few of the papers in hard copy, in case anyone is interested.  I think that the attack was on carbon in this instance.  This might be a start if anyone is interested:  Lecocq, J., and A.R.Todd, J. Chem. Soc., 2381 (1954).

Offline wildfyr

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Re: LiCl hydrolysis of Methyl esters
« Reply #4 on: March 26, 2020, 08:44:55 AM »
Holly, you are probably right that LiI may work better, however A. I wonder if it will dealkylate more than just methyl esters B. its a little less common to be lying around in a stockroom C. iodine salts often have to be purified before use because they generate I2 while sitting on a shelf. LiCl won't generate Cl2 at ambient temps.

Offline hollytara

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Re: LiCl hydrolysis of Methyl esters
« Reply #5 on: March 26, 2020, 12:24:41 PM »
Sounds like a research project!

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