100 Years of Baeyer–Villiger Oxidations

TLDR

The Baeyer–Villiger oxidation, first reported in 1899, has a history marked by early controversy over the instability of its peroxide oxidant and a long debate over its mechanism. The review examines the Baeyer–Villiger reaction, covering its discovery, mechanism, competitive migration, and rate‑determining step. The authors discuss the competitive migration pathways and identify the rate‑determining step in the Baeyer–Villiger oxidation. The review confirms that the mechanism involves a nucleophilic attack by the peroxide, a rearrangement that retains stereochemistry, and rules out 1,2,4,5‑tetraoxocyclohexane as an intermediate.

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.