Epoxidation of Terminal Alkenes with Oxygen and 2-Ethyl Hexanal, without Added Catalyst or Solvent

Practical Epoxidation of Olefins Using Air and Ubiquitous Iron-Based Fluorous Salen Complex

The epoxidation of olefins by substituting "air" for potentially harmful oxidants was achieved using an oxidation method that integrated a fluorous iron(III) salen catalyst derived from common metals and pivalaldehyde. Several aromatic disubstituted olefins were converted into their corresponding epoxides with high efficiency and quantitative yields. This reaction represents an environmentally friendly oxidation process that utilizes an abundant source of air and employs a readily available metal, iron, in the form of salen complexes, making it an environmentally conscious oxidation reaction.

Aldehyde-catalyzed epoxidation of unactivated alkenes with aqueous hydrogen peroxide

The organocatalytic epoxidation of unactivated alkenes using aqueous hydrogen peroxide provides various indispensable products and intermediates in a sustainable manner. While formyl functionalities typically undergo irreversible oxidations when activating an oxidant, an atropisomeric two-axis aldehyde capable of catalytic turnover was identified for high-yielding epoxidations of cyclic and acyclic alkenes. The relative configuration of the stereogenic axes of the catalyst and the resulting proximity of the aldehyde and backbone residues resulted in high catalytic efficiencies. Mechanistic studies support a non-radical alkene oxidation by an aldehyde-derived dioxirane intermediate generated from hydrogen peroxide through the Payne and Criegee intermediates.

Epoxidation using molecular oxygen in flow: facts and questions on the mechanism of the Mukaiyama epoxidation

Mukaiyama reaction was performed G/L continuous-flow microreactor. In less than 5 minutes at room temperature, cyclooctene was efficiently transformed to the corresponding epoxide using O₂ as oxidant and aldehyde as co-reductant.