Use of Ionic Liquids as Reagents for Demethylation - Lactonisation

02 April 2008

Process chemists at Organon published a paper on the use of ionic liquids for the cleavage of aromatic methyl ethers, in 20031. The reagent also seems to effective for the cleavage of aromatic benzyl and allyl ethers. The same group have now published a follow up paper2 describing a one-pot demethylation – lactonisation sequence effected with an ionic liquid to produce substituted benzo[c]chromen-6-ones. In addition this method has been carried out on a multi-kilogram scale (6.75kg of substrate) as shown below.

1. G.J. Kemperman,* T.A. Roeters, and P.W Hilberink (Organon), Eur. J. Org. Chem., 2003, 1681-1686.

2. G.J. Kemperman,* B. Ter Horst, D. Van de Goor, T.A. Roeters, J. Bergwerff, R. Van der Eem, and J. Basten (Organon), Eur. J. Org. Chem., 2006, 3169-3174.