I need to condense alkoxyphenyl lithium with substituted anthroquinone, in-situ. But the anthraquinone derivative that I am using is insoluble in the THF. Reaction yield is too little even when mixture was refluxed for a whole day.
Could anyone please suggest any solvents for lithiated condensation other than THF, in which polyaromatic moieties are soluble or could you please suggest any alternative methods?
Try DME (1,2-dimethoxyethane). It's generally a better solvent than THF, but harder to get really dry. I'd distill it from sodium/benzophenone just before use.
You have got two good suggestions already. I may add that sometimes Me-THF is a better solvent for this kind of reactions. Also you may try a co-solvent, for example, even toluene may help since it is aromatic solvent (like your substrate).
Teodoro Kaufman, Mark Minton, Vladimir Khlebnikov - Thanks a lot for your helpful suggestions ! Appreciate it.
You may also try using DMPU - that would be a safer alternative to HMPA.
THF: Benzene (1:1) works fine, you can even lower your ratios if alkoxyphenyl lithium does not tend to crash out of solution when using minimum possible THF. check out this paper: DePue, J. S.; Collum, D. B. J. Am. Chem. Soc. 1988, 110, 5518.
Hi,
If I didn't understand the question wrong, would it be possible to use 12-crown-4 ether to trap Li+ during the course of reaction possibly together with the use of a co-solvent?
Good luck
Try other oxygenated solvent as: Ethyl Ether, DME, Dioxane, Diglyme or you can try a mixture of oxygenated solvent as: Ethyl Ether-THF, THF-Dioxane, THF-DME
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