The role of hydrogen bonding in controlling the selectivity of Diels–Alder reactions in room-temperature ionic liquids

Abstract
The reaction of cyclopentadiene with methyl acrylate has been investigated in a range of ionic liquids. The origin of the endo-selectivity for the reactions and associated rate enhancements has been attributed to a hydrogen bond formed between the cation of the ionic liquid and the methyl acrylate.