Recyclable 2nd generation ionic liquids as green solvents for the oxidation of alcohols with hypervalent iodine reagents

Alcohols undergo smooth oxidation with iodoxybenzoic acid (IBX) or with Dess–Martin-Periodinane (DMP) in hydrophilic [bmim]BF4 and hydrophobic [bmim]PF6 ionic liquids at room temperature under mild conditions to afford the corresponding carbonyl compounds in excellent yields with high selectivity. IBX and DMP promoted oxidations are faster in ionic liquids when compared to conventional solvents such as DMSO, DMF, EtOAc and H2O. The recovery of the byproduct iodosobenzoic acid (IBA) is especially simple in ionic liquids. The recovered ionic liquids can be recycled in subsequent reactions with consistent activity.