Sciencemadness Discussion Board

oxymercuration cosolvent choice

jwarr - 13-9-2010 at 06:49

From what I've read, it seems the prototypical cosolvent for an oxymercuration reaction is THF. Since THF isn't readily available to me, I'm looking for alternatives. Obviously alcohols are out of the question. I'm fairly certain ether would be fine, but I'd like to avoid distilling it from starting fluid. Can anyone suggest another suitable cosolvent that is fairly easy for your average joe chemist to obtain? Am I right in thinking that solubility in water and lack of acidity are the two major considerations?

Nicodem - 14-9-2010 at 04:24

Quote: Originally posted by jwarr  
From what I've read, it seems the prototypical cosolvent for an oxymercuration reaction is THF.

You gave no references for what you read, so you will not obtain any proper answer.
Quote:
Since THF isn't readily available to me, I'm looking for alternatives. Obviously alcohols are out of the question. I'm fairly certain ether would be fine, but I'd like to avoid distilling it from starting fluid. Can anyone suggest another suitable cosolvent that is fairly easy for your average joe chemist to obtain? Am I right in thinking that solubility in water and lack of acidity are the two major considerations?

Diethyl ether is unlikely to dissolve much of Hg salts though it depends on which salt you intent to use. THF is most certainly the simplest aplicable solvent you can obtain. Solubility in water and lack of acidity of the solvent have nothing to do with oxymercuriations. Acetic acid is an acid and yet it works fine for oxymercuriations where the acetoxy group is introduced. Acetonitrile works fine for introducing the acetamido group via mercuriation. But since you don't say what you ask about, nobody can suggest you some alternative solvent instead of THF. You can try with 1,4-dioxane though - often where THF works dioxane might also.

jwarr - 14-9-2010 at 14:32

Quote:

You gave no references for what you read, so you will not obtain any proper answer.

My apologies.

The Oxymercuration-Demercuration of Representative Olefins. A Convenient, Mild Procedure for the Markovnikov Hydration of the Carbon-Carbon Double Bond
J. Am. Chem. Soc., 1967, 89 (6), pp 1522–1524

The substrate is 2,4,5-trimethoxy-5-(2-propenyl)-benzene.
Quote:
Solubility in water and lack of acidity of the solvent have nothing to do with oxymercuriations

Obviously I don't want something such as methanol in the solution competing with H2O for the addition. I guess what I am trying to avoid is nucleophiles, not acids. Completely different, my mistake.

As for solubility in water, isn't it important that my substrate and the water attacking it be in the same phase? I've only got two semesters of organic under my belt, so please if this is completely out of whack let me know.