Experimental and Computational Studies on Substituent Effects in Reactions of Peracid–Aldehyde Adducts

Liquid phase oxidation of six branched and four linear aldehydes by dioxygen and m-chloroperbenzoic acid was studied experimentally. 2-Substituted (α-branched) aldehydes reacted to give formates (via Bayer–Villiger mechanism) whereas the related linear saturated aldehydes were converted to the corresponding carboxylic acids. Formation of both these products can be rationalized via rearrangement reactions of peracid–aldehyde adducts 1. Computational studies employing DFT methods at the DNPP level with the Spartan program (v5.0) were carried out in order to understand properties of those adducts. Conformational properties of the adducts 1 were found to shed light on the differences observed in the reactions of linear and branched adducts.