Enantioselective Baeyer-Villiger oxidation

Mihovilovic, M.D., Rudroff, F. and Grotzl, B., Enantioselective Baeyer-Villiger oxidations. Curr. Org. Chem., 2004, 8, 1057-1069. 

SCHEME 170. Pt-catalyzed enantioselective Baeyer-Villiger oxidation of cyclic meso-ketones with H2O2 using chiral diphosphine hgands... 

SCHEME 169. Chiral Pt complexes 231 employed as asymmetric inductors in the kinetic resolution of racemic cyclic ketones formed by enantioselective Baeyer-Villiger oxidation... 

Since the isolation of the oxygenating enzyme and recycling of the cofactor is still difficult for large-scale preparations, the use of whole microorganisms would seem to be advantageous. Whole cells of Acinetobacter are well suited for enantioselective Baeyer-Villiger oxidation of cyclic ketones when a lactone hydrolase inhibitor is used or a hydrolase deficient mutant is... 

Oxidations catalyzed by monooxygenases Oxygenations of C-H and C=C bonds forming alcohols, epoxides enantioselective Baeyer-Villiger oxidations of ketones to chiral lactones and of sulfides to chiral sulfoxides nuclear and side-chain hydroxylation of aromatic compounds. 

Fig. 2.16 Catalytic enantioselective Baeyer-Villiger oxidation of prochiral ketones, using H2O2 (in the form of a urea-adduct) as oxygen equivalent in stoichiometric amounts (a) 3-phenylcyclobutanone, (b) tricyclic cyclo-butanone.

Another method for enantioselective Baeyer-Villiger oxidations was developed by Strukul [28,29]. His catalytic system is based on cationic platinum-diphosphine complexes which activate H2O2 to oxidize cycHc ketones (Eq. 5). 

A third variant of a metal-catalyzed enantioselective Baeyer-Villiger oxidation of cyclobutanones was reported by Lopp [30]. Up to 75% ee was achieved using the system for the epoxidation of allylic alcohols developed by Sharpless, i.e., Ti(Oi-Pr)4, chiral diethyl tartrate, and ferf-butyl hydroperoxide (Eq. 6). 

Apart from the asymmetric metal catalysis, enantioselective Baeyer-Villiger oxidations mediated by enzymes have been known for some time [32,33,34]. Both whole-cell cultures and isolated enzymes, usually flavin-dependent monooxygenases, can be used to oxidize ketones enantioselectively. For future improvements in the asymmetric Baeyer-VilHger oxidation the use of chiral Lewis acids in combination with an appropriate oxidant seems worthy of intensive investigation. 

Figure 16.5-38. Enantioselective Baeyer-Villiger oxidation of a tricyclic ketone by Type 1 and Type 2 BVMOs.

Scheme 2.165 Regio- and enantioselective Baeyer-Villiger oxidation using cloned Baeyer-Villigerases exhibiting desymmetrization, and classic and nonclassic kinetic resolution...

Hydroxo-bridged dinuclear complexes, [Pt(P-P)(/u-OH)]2 (where P-P = DIOP, BINAP, NORPHOS, MeDUPHOS, and BPPM) as precursors have been used for the enantioselective Baeyer-Villiger oxidation of ketones (290). The platinum(O) catalyst precursor, Pt(MeDUPHOSXfrans-stylbene), catalyzes the asymmetric hydrophosphination of activated olefins (291). 

Although more than one century has gone by since its discovery in 1899, the Baeyer Villiger reaction is still far from being fully developed. In particular, there are only a few catalyst systems which afford products from the Baeyer-Villiger oxidation of 3-substituted cyclobutanones in more than 80% ee. The first example of the enantioselective Baeyer-Villiger oxidation of 3-substituted cyclobutanones catalysed by a chiral organocatalyst and 30%... 

Ito, K., Ishii, A., Kuroda, T, et al. (2003). Asymmetric Baeyer—ViUiger Oxidation of Prochi-ral Cyclobutanones Using a Chiral Cationic PaUadium(II) 2-(Phosphinophenyl)Pyridine Complex as Catalyst, Synlett, 5, pp. 643-646 Maikov, A., Friscourt, R, Bell, M., et al. (2008). Enantioselective Baeyer-Villiger Oxidation Catalyzed by PaUadium(II) Complexes with Chiral P,N-Ligands, J. Org. Chem., 73, pp. 3996-4003. 

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. 

Zhou, L., Liu, X., Ji, J., Zhang, Y, Hu, X., Lin, L., Feng, X. (2012). Enantioselective Baeyer-Villiger oxidation desymmetrization of meso cyclic ketones and kinetic resolution of racemic 2-arylcyclohexanones. Journal of the American Chemical Society, 134, 17023-17026. 

In y-lactone synthesis through enantioselective Baeyer-Villiger oxidation, notable result was demonstrated by Mura-hashi et al. in 2002 (Scheme 8) [18]. They successfully found that planar-chiral bisflavin tethered by frans-cyclohexane-l,2diamine backbone works as an effective catalyst for enantioselective Baeyer-Villiger oxidation of cyclobutanone 19a with H2O2. Ding et al. recently reported chiral phosphoric acid 22a-catalyzed reaction with up to 88% ee of (R)-20a [19]. 

Bolm et al. reported enantioselective Baeyer-Villiger oxidations catalyzed by chiral Mg(II) complexes (Scheme 4.19) [18]. The reaction of 3-phenylcyclobutanone (63) with cumene hydroperoxide (CMHP) as an oxidant proceeded in the presence of 25-50 mol% each of (J )-BINOL and MgH, and the corresponding lactone (64)... 

Synthesis of lactones via regio-and enantioselective Baeyer-Villiger oxidation of a racemic cyciic ketone with a recombinant whoiecatalyst containing a Baeyer-Viiiiger monooxygenase. 

Maikov AV, Friscourt F, Bell M, Swarbrick ME, Kocovsky P. Enantioselective Baeyer-Villiger oxidation catalyzed by palla-dium(II) complexes with chiral P,N-ligands. J. Org. Chem. 2008 73 3996 003. 

Watanabe A, Uchida T, Ito K, Katsuki T. Highly enantioselective Baeyer-Villiger oxidation using Zr(salen) complex as catalyst. Tetrahedron Lett. 2002 43 4481-4485. 

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. 

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