Baeyer-Villiger oxidation cyclohexanone, hydrogen peroxide

In 2001, Albrecht Berkessel and Nadine Vogl reported on the Baeyer-Villiger oxidation with hydrogen peroxide in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as solvent in the presence of Brpnsted acid catalysts such as para-toluenesulfonic acid (equation 85) . Under these conditions cyclohexanone could be selectively transformed into the corresponding lactone within 40 min at 60 °C with a yield of 92%. Mechanistic investigations of Berkessel and coworkers revealed that this reaction in HFIP proceeds by a new mechanism, via spiro-bisperoxide 234 as intermediate, which then rearranges to form the lactone. The study illustrates the importance of HFIP as solvent for the reaction, which presumably allows the cationic rearrangement of the tetroxane intermediates. 

The Baeyer-Villiger oxidation of cyclohexanone with aqueous hydrogen peroxide has been reported to result in a thermally activated radical leading to the formation of adipic acid. An oxidative rearrangement of 2-furylcarbamates to A-Boc-5-hydroxypyrrol-2(5//)-ones has been reported (Scheme 63). ... 

Paneghetti, C., Gavagnin, R., Pinna, R, et al. (1999). New Chiral Complexes of Platinum(II) as Catalysts for the Enantioselective Baeyer-Villiger Oxidation of Ketones with Hydrogen Peroxide Dissymmetrization of Meso-Cyclohexanones, Organometallics, 18, pp. 5057-5065. 

Hawkins has used permaleic acid for the Baeyer-Villiger oxidation of cyclohexanone to obtain cyclohexanolide in a 90-100% yield. He has shown that if any free hydrogen peroxide is present, the yield could suffer... 

Paneghetti C, Gavagiun R, Piima F, Strukul G. New chiral complexes of platinum(II) as catalysts for the enantioselective Baeyer-Villiger oxidation of ketones with hydrogen peroxide dissymmetrization of meso-cyclohexanones. Organometallics 2001 18 5057 5065. 

In fluorinated alcohol solvents, nonstrained ketones such as cyclohexanone (1) undergo oxidation to lactones in the presence of hydrogen peroxide and catalytic amounts of Brpnsted acids (Berkessel and An-dreae 2001 Berkessel et al. 2002). Unlike the classical Baeyer-Villiger reaction, ketone oxidation with H2O2 in e.g. HFIP proceeds via a spiro-bisperoxide 2 intermediate (Scheme 1). In contrast to other solvents, the acid-catalyzed rearrangement of the spiro-bisperoxide 2 to two equivalents of the product lactone 3 proceeds rapidly and cleanly in HFIP. Preliminary calculations indicate active participation of the fluorinated alcohol solvent in the rate-determining step also in this case. 

The Baeyer-Villiger rearrangement of cyclohexanone and acetophenone with TS-I/H2O2 proved to be poorly selective [117]. Notably, Ti-P and Sn-P have different chemoselectivities in the oxidation of unsaturated ketones, leading selectively to corresponding epoxides and lactones, respectively [118]. The different oxidation pathways were attributed to the preferential adsorption of hydrogen peroxide on Ti-sites and of the carbonyl group on Sn-sites. 

The CL monomer is obtained by the traditional Baeyer-Villiger reaction, starting from cyclohexanone as substrate. However, this synthetic route is not environmentally friendly, which has involved the development of two greener routes (1) use of a peroxycarboxylic acid (such as 3-chloroperbenzoic acid or peracetic acid) in dichloromethane at 40 ° C, and (2) use of hydrogen peroxide as oxidizer and zeolite/tin catalysis.The second process is considered the greenest because the main by-product is exclusively water and the tin-impregnated zeolite is an environmentally friendly catalyst. Nowadays, CL is produced by several manufacturers like BASF (USA), Perstorp (UK), and Daicel Chemical Industries Ltd. (Japan). 

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