Solvate Ionic Liquids as Reaction Media for Electrocyclic Transformations

Solvate ionic liquids (SILs) consisting of lithium bis(trifluoromethylsulfonyl)imide dissolved in tri- or tetraglyme have recently emerged as a novel class of ionic liquids. Herein, the first use of solvate ionic liquids as a replacement for molecular solvents in electrocyclization reactions is reported. The SILs promoted both Diels-Alder and [2+2] cycloaddition reactions, compared to an appropriate molecular solvent, and 5 M lithium perchlorate in diethyl ether. The Gutmann acceptor number (AN) of these solvate ionic liquids has also been determined by P-31 NMR spectroscopy to be 26.5, thus being modest Lewis acids.