Epoxidation and Baeyer-Villiger oxidation using hydrogen peroxide and a lipase dissolved in ionic liquids

Epoxidation and Baeyer-Villiger oxidation of olefins and (cyclic) ketones were successfully carried out in hydrogen-bond-donating (HBD) ionic liquids, using a lipase-catalysed cascade and hydrogen peroxide as the terminal oxidant. The effect of the ionic liquids turned out to be twofold. The HBD ionic liquids exhibited a substantial positive solvent effect on the second step of the cascade, namely the oxygen transfer by peracid. In addition, we found that the Candida antarctica B lipase (CaLB) dissolved in 1-(3-hydroxypropyl)-3-methyl imidazolium nitrate 1a and 1-butyl-3-methylimidazolium nitrate 2a. This stable enzyme-ionic liquid solution opens the possibility for continuous chemical processing.