In the Baeyer-Villiger reaction

The original library of 10 000 clones used in the Baeyer-Villiger reaction [89] was screened for performance as potential catalysts in the sulfoxidation [32]. This led to the discovery of at least 20 mutants having enantiomeric excess values in the range of 85-99%, some being (R) selective and others being (S) selective. Five mutants resulting in enantiomeric excess values of >95% were sequenced (Table 2.2) [32]. 

A new transition state (7) of the addition step in the Baeyer-Villiger reaction was found by B3LYP calculations. The role of proton acceptor is played by the carbonyl-oxygen atom, and the free energy barrier is lower than that previously estimated. This finding changes the mechanism for the acid catalysis.231... 

Alternatively, acids can activate peroxides, for example, in the Baeyer-Villiger reaction (394) ... 

To finish this chapter, a Beckmann rearrangement that is not all that it seems, f-Butyl groups migrate well in the Baeyer-Villiger reaction and, indeed, Beckmann rearrangement of this compound appears to be quite normal too. 

In the Baeyer-Villiger reaction, a ketone is oxidized to an ester by persulfuric acid, H2S05. 

The acylations of a-alkoxy hydroperoxides such as (79) furnish peroxy esters that are related to the intermediate produced in the Baeyer-Villiger reaction. " The peroxy ester undergoes the Criegee rearrangement to a dioxonium ion which in turn is converted into an ester. Thus, ozonolysis of (+)-( )-dihydrocarvone (78) affords a 1 1 mixture of diastereomers (79). Acetylation and rearrangement... 

Winnik, M. A., Stoute, V., Fitzgerald, P. Secondary deuterium isotope effects in the Baeyer-Villiger reaction. J. Am. Chem. Soc. 1974, 96, 1977-1979. 

Chandrasekhar, S., Roy, C. D. Evidence for a stereoelectronic effect in the Baeyer-Villiger reaction. Introducing the intramolecular reaction. Tetrahedron Lett. 1987, 28, 6371-6372. 

I crmaleic acid can be used in the Baeyer-Villiger reaction, as illustrated for the case of cyclooctanone. It epoxidizes terminal olehns eflSciently at a low temperature l -oclene affords the epoxide in 80% yield at 0° but at 25° the yield is only 40%. In I he case of the more reactive internal olefins the epoxide ring is cleaved even at 0° to give the diol monomaleate. Aromatic amines with electron-withdrawing substituents MIC oxidized to nitro compounds. 

Oxidation. Hexafluoroacetone (available from Aldrich) and hydrogen peroxide form a complex which functions as a peracid. Thus it can be used in the Baeyer-Villiger reaction and for oxidation of a primary aromatic amine to a nitro compound. Preliminary results, however, indicate that the adduct is less powerful than pertrifluoroacetic acid.1... 

Activation for the Michael reaction could be by C02Et group or enamine formation. Ring expansion of (16) to <14> is unambiguous as only the more substituted side chain migrates, as in the Baeyer-Villiger reaction (Chapter... 

The study to predict the migrating group in the Baeyer-Villiger reaction has been scrutinized by several authors. As previously stated, conformational, steric, and... 

Although most peroxyacids can be used in the Baeyer-Villiger reaction, trifluoroperoxyacetic acid is one of the more efficient reagents for this rearrangement. House gave an example in which 301 was selectively... 

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