Ionic liquid assisted synthesis of six-membered oxygen heterocycles

Due to special properties of ionic liquids (ILs) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environment friendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. The investigation for replacement of organic solvents in organic synthesis is a growing area of interest due to increasing environmental issues. Therefore, ILs have attracted the attention of chemists and act as catalyst and reaction medium in organic reaction with high activity. There is no doubt that ILs have become a major subject of study for modern chemistry. In comparison to traditional processes the use of ILs resulted in improved, complimentary or alternative selectivities in organic synthesis. The aim of present review is to focus on the applications of ILs for the synthesis of six-membered oxygen heterocycles (pyrans, chromenes, coumarins and dioxanes).