Baeyer-Villiger Oxidation restricted to Ketones

Question

According to Wikipedia, Baeyer Villiger oxidation occurs at the electron deficient oxygen site, with elimination of the carboxylate ion, and migration of an R group. But it is restricted to ketones and lactones. Why are aldehydes not included in it? Moreover, since migratory amplitude of hydrogen is lower than alkyl or aryl, shouldn't aldehydes be more prone to participate in this reaction?

Answer 1

May be Baeyer Villiger oxidation is not for aldehydes in the past. But that has changed recently (Ref.2). The abstract of this reference states that:

A conceptually distinct, modern strategy for Baeyer−Villiger oxidation (BVO) was developed. Our novel method involves initial hydration of water to carbonyl compounds, followed by ligand exchange of hypervalent aryl-$\lambda^3$-bromane on bromane(III) with the resulting hydrate, yielding a new type of activated Criegee intermediate. The intermediate undergoes BV rearrangement and produces an ester via facile reductive elimination of an aryl-$\lambda^3$-bromanyl group, because of the hypernucleofugality. The novel strategy makes it possible to induce selectively the BV rearrangement of straight chain primary aliphatic as well as aromatic aldehydes, which is missing in the classical BVO: for instance, octanal and benzaldehyde afforded rearranged formate esters with high selectivity (> 95%) under our conditions, while the attempted classical BVO produced only carboxylic acids. This firmly establishes the powerful nature of new methodology for BVO.

The suggested mechanism and comparison it with classical Baeyer−Villiger oxidation is shown in following scheme $(\bf{A})$:

The part $\bf{B}$ of the scheme depicted computational calculation of energy diagram for acetaldehyde oxidation.

In addition, similar oxidation of acetal (an aldehyde derivative) to ester have been known for years. For example, conversion of cyclic acetals to hydroxy esters by mCPBA oxidation is published in 2002 (Ref.2).

Reference:

1. Masahito Ochiai, Akira Yoshimura, Kazunori Miyamoto, Satoko Hayashi, Waro Nakanishi, "Hypervalent $\lambda^3$-Bromane Strategy for Baeyer−Villiger Oxidation: Selective Transformation of Primary Aliphatic and Aromatic Aldehydes to Formates, Which is Missing in the Classical Baeyer−Villiger Oxidation," J. Am. Chem. Soc. 2010, 132(27), 9236–9239 (https://doi.org/10.1021/ja104330g).
2. Jin Yeon Kim, Hakjune Rhee, Misoo Kim, "Conversion of Cyclic Acetals to Hydroxy Esters by MCPBA Oxidation," Journal of the Korean Chemical Society 2002, 46(5), 479-483 (DOI: 10.5012/jkcs.2002.46.5.479).