Ionic Liquid Baeyer-Villiger

The Baeyer-Villiger oxidation of cyclic ketones was also achieved by the MTO/H2O2 system in the ionic liquid [BMIM][BF4 [78] (Scheme23). Kinetic investigations have additionally been performed in order to follow the formation of the catalytically active peroxorhenium intermediates in the RTILs [81,82]. 

Compounds in this class are usually made from specific precursors with the ultimate functionalities appearing in the starting materials. Syntheses in which one new bond is formed (cyclizations) usually involve substitution or condensation reactions. Two new closures with potentially some generality have been noted in this chapter. One of the intramolecular Diels-Alder reactions (see Section 13.12.8.1) and the other RCM (see Section 13.12.8.1). The Baeyer-Villiger reaction is still very much used for the preparation of lactones. A supported catalyst and a recyclable catalyst carried in an ionic liquid have been introduced for use in Baeyer-Villiger oxidations from other areas. 

Baeyer-Villiger oxidations in ionic liquids have also been reported using either m-chloroperbenzoic acid1821 or H202 as the oxidant.1831 In the latter case Sn-(3-molecular sieves served as the catalyst. 

A review of oxidation reactions in imidazolium ionic liquids has addressed oxidations of alcohols, aromatics, alkanes, and sulfur-containing compounds and the Baeyer-Villiger and Corey-Chaykovsky methods. ... 

Roberta B, Antonietta C, Giancarlo F, Antonella G (2003) CHjReOj/HjOj in room temperature ionic liquids an homogeneous recyclable catalytic system for the Baeyer-Villiger reae-tion. Tetrahedron Lett 44 8991-8994... 

Examples of applying biphasic system to catalyzed reactions, such as phase-transfer catalysis, show the efficiency over stoichiometric reactions. In a typical catalytic biphasic system, one phase contains the catalyst while the substrate is in the second phase. In some systems, the catalyst and substrates are in the same phase while the product produced is transferred to the second phase. In a typical reaction, the two phases are mixed during the reaction and after completion, the catalyst remains in one phase ready for recycling while the product can be isolated from the second phase. The most common solvent combination consists of an organic solvent combined with another immiscible solvent, which, in most applications, is water. However, there are few examples of suitable water-soluble and stable catalysts, therefore various applications are limited to some extent [4]. Immiscible solvents other than water are recently becoming more applicable in biphasic catalysis due to the better solubility and stability of various catalysts in such solvents. For example, ionic liquids and fluorous solvents have many successful applications in liquid-liquid biphasic syntheses such as Heck reactions and hydroformylations using ionic liquid media, or Baeyer-Villiger reactions... 

Chrobok, A. (2010). Baeyer-Villiger Oxidation of Ketones in Ionic Liquids Using Molecular Oxygen in the Presence of Benzaldehyde, Tetrahedron, 66, p>p. 2940-2943Chrobok, A. (2010). The Baeyere-Villiger Oxidation of Ketones with Oxone in the Presence of Ionic Liquids as Solvents, Tetrahedron, 66, pp. 6212-6216... 

---