Mg(OTf)₂ + ionic liquid - recyclable catalytic system in diels-alder reaction

A comparative study of Diels-Alder reaction between cyclopentadiene and dimethyl maleate in catalytic system is reported. The catalytic system was formed from ionic liquid which was made of N-hexylpyridinium bis(trifluoromethylsulfonyl)imide and magnesium trifluoromethanesulfonate. The yields, TONs, TOFs and endo:exo ratios were calculated. The optimal catalyst concentration was found in order to obtain the mixture of endo, exo isomers with the highest yields. Moreover recycling of the catalytic system consisting of Mg(OTf)₂ (2 mol%) and ionic liquid was performed. The distillation was noticed to be a better product removal method than extraction by organic solvent, taking into consideration both the TON and TOF values.