Selective Oxidative Cleavage of the C-C Bond in α,β-Epoxy Ketone into Carbonyl Compounds

This method afforded aromatic carbonyl compounds under TBHP via selective oxidative cleavage of the C-C bond in α,β-epoxy ketones. Aromatic acid came from the aroyl section, and aromatic aldehyde came from the other aromatic group. TBHP acted as a free radical initiator and oxidant. The reaction within the solvent went through a ring-opening addition, cleavage of the C-C bond in the ethylene oxide section, and oxidation, affording the target compounds in moderate to good yields. The HPLC yield of aromatic aldehyde was up to 91%. The HPLC yield of aromatic acid was up to 99%. The reaction under solvent-free conditions gave two kinds of aromatic acids coming from different moieties of α,β-epoxy ketone via the further oxidation of aromatic aldehyde. The substituent effect was discussed, and the reaction mechanism was proposed. This method allowed the reaction to occur in a simple system metal-free.

Tracking down the brominated single electron oxidants in recent organic red-ox transformations: photolysis and photocatalysis

A wide range of organic and inorganic brominated compounds including molecular bromine have been extensively used as oxidants in many organic photo-redox transformations in recent years, an area of ever growing interest because of greener and milder approaches. The oxidation power of these compounds is utilized through both mechanistic pathways (by hydrogen atom transfer or HAT in the absence of a photocatalyst and a combination of single electron transfer or SET and/or HAT in the presence of a photocatalyst). Not only as terminal oxidants for regeneration of photocatalysts, but brominated reactants have also contributed to the oxidation of the reaction intermediate(s) to carry on the radical chain process in several reactions. Here in this review mainly the non-brominative oxidative product formations are discussed, carried out since the last two decades, skipping the instances where they acted as terminal oxidants only to regenerate photocatalysts. The reactions are used to generate natural products, pharmaceuticals and beyond.