100 Years of Baeyer–Villiger Oxidations

Abstract

In the present review, we report the discovery of the formation of esters and lactones by oxidation of ketones with a peroxide derivative, namely the Baeyer–Villiger reaction. This reaction was first reported by Adolf von Baeyer and Victor Villiger a century ago in 1899, just one year after the oxidant they used (KHSO5) has been described. Furthermore, Baeyer and Villiger established the composition of this new inorganic peroxide and showed that its instability was the reason of a controversy between several European chemists between 1878 and 1893. For the first 50 years the mechanism of the Baeyer–Villiger reaction was a matter of debate. A side product, 1,2,4,5‐tetraoxocyclohexane, was ruled out as an intermediate in the ester formation by Dilthey. Criegee postulated a nucleophilic attack of the oxidant on the carbonyl group. This mechanism was confirmed by von E. Doering by a labeling experiment with [18O]benzophenone. The rearrangement step occurs with retention of the stereochemistry at the migrating center. The competitive migration and the rate‐determining step are also discussed in this review.

The Role of Hydrogen Bonds in Baeyer−Villiger Reactions

“…However, the difference of the two free activation energies are not large [27.30 (TS1) − 24.14 (TS3) = 3.16 kcal/mol)] and are critical. Thus, the present calculated result would be consistent with the postulate that “in the B−V reaction several steps can be rate-determining depending on the reaction conditions and the substrate itself” 2b. Palmer and Fry reported a rate constant of the second-order (4.53 × 10 -3 L mol -1 s -1 ) at 32 °C in CHCl 3 for the B−V reaction between acetophenone and MCPBA .…”

The Role of Hydrogen Bonds in Baeyer−Villiger Reactions

“…However, the difference of the two free activation energies are not large [27.30 (TS1) − 24.14 (TS3) = 3.16 kcal/mol)] and are critical. Thus, the present calculated result would be consistent with the postulate that “in the B−V reaction several steps can be rate-determining depending on the reaction conditions and the substrate itself” 2b. Palmer and Fry reported a rate constant of the second-order (4.53 × 10 -3 L mol -1 s -1 ) at 32 °C in CHCl 3 for the B−V reaction between acetophenone and MCPBA .…”

Reinvestigation of Acetophenones Oxidation by Performic Acid in Formic Acid

“…The Gibbs free energy barrier of the migration step for all of the studied BV reactions is in accord with the observation that the energies decrease with the electron-releasing aptitude of the group (H > 4-methyl > 3,4-dimethoxy), making the TS2 more stable …”

Comparison of Epoxidation and Baeyer−Villiger Reaction Pathways for Ti(IV)−H2O2 and Sn(IV)−H2O2

“…The activation barriers for this step are 3-4 kcal/mol lower for 2-methyl-3-pentanone than those for acetone because the electron-donating alkyl groups on the migrating R carbon promote nucleophilic attack of the peroxo bond. The same trend is generally observed for Baeyer-Villiger oxidations with traditional peroxycarboxylic acid oxidants [43][44][45][46] and has also been observed for platinum-catalyzed Baeyer-Villiger oxidations with hydrogen peroxide. 47 The relative reaction rates for tin and titanium can be estimated with the same definition of ∆G total used above; the values are reported in Table 11.…”

The Role of Hydrogen Bonds in Baeyer−Villiger Reactions

“…However, the difference of the two free activation energies are not large [27.30 (TS1) − 24.14 (TS3) = 3.16 kcal/mol)] and are critical. Thus, the present calculated result would be consistent with the postulate that “in the B−V reaction several steps can be rate-determining depending on the reaction conditions and the substrate itself” 2b. Palmer and Fry reported a rate constant of the second-order (4.53 × 10 -3 L mol -1 s -1 ) at 32 °C in CHCl 3 for the B−V reaction between acetophenone and MCPBA .…”

Reinvestigation of Acetophenones Oxidation by Performic Acid in Formic Acid

“…The Gibbs free energy barrier of the migration step for all of the studied BV reactions is in accord with the observation that the energies decrease with the electron-releasing aptitude of the group (H > 4-methyl > 3,4-dimethoxy), making the TS2 more stable …”

Comparison of Epoxidation and Baeyer−Villiger Reaction Pathways for Ti(IV)−H2O2 and Sn(IV)−H2O2

“…The activation barriers for this step are 3-4 kcal/mol lower for 2-methyl-3-pentanone than those for acetone because the electron-donating alkyl groups on the migrating R carbon promote nucleophilic attack of the peroxo bond. The same trend is generally observed for Baeyer-Villiger oxidations with traditional peroxycarboxylic acid oxidants [43][44][45][46] and has also been observed for platinum-catalyzed Baeyer-Villiger oxidations with hydrogen peroxide. 47 The relative reaction rates for tin and titanium can be estimated with the same definition of ∆G total used above; the values are reported in Table 11.…”

The Role of Hydrogen Bonds in Baeyer−Villiger Reactions

“…However, the difference of the two free activation energies are not large [27.30 (TS1) − 24.14 (TS3) = 3.16 kcal/mol)] and are critical. Thus, the present calculated result would be consistent with the postulate that “in the B−V reaction several steps can be rate-determining depending on the reaction conditions and the substrate itself” 2b. Palmer and Fry reported a rate constant of the second-order (4.53 × 10 -3 L mol -1 s -1 ) at 32 °C in CHCl 3 for the B−V reaction between acetophenone and MCPBA .…”

Reinvestigation of Acetophenones Oxidation by Performic Acid in Formic Acid

“…The Gibbs free energy barrier of the migration step for all of the studied BV reactions is in accord with the observation that the energies decrease with the electron-releasing aptitude of the group (H > 4-methyl > 3,4-dimethoxy), making the TS2 more stable …”

Comparison of Epoxidation and Baeyer−Villiger Reaction Pathways for Ti(IV)−H2O2 and Sn(IV)−H2O2

“…The activation barriers for this step are 3-4 kcal/mol lower for 2-methyl-3-pentanone than those for acetone because the electron-donating alkyl groups on the migrating R carbon promote nucleophilic attack of the peroxo bond. The same trend is generally observed for Baeyer-Villiger oxidations with traditional peroxycarboxylic acid oxidants [43][44][45][46] and has also been observed for platinum-catalyzed Baeyer-Villiger oxidations with hydrogen peroxide. 47 The relative reaction rates for tin and titanium can be estimated with the same definition of ∆G total used above; the values are reported in Table 11.…”