2-Bromoanthraquinone as a highly efficient photocatalyst for the oxidation of sec-aromatic alcohols: experimental and DFT study

Abstract

Anthraquinones are recognized as high efficiency photocatalysts which can perform various redox reactions in aqueous or organic phases.

Catalyst-free aerobic photooxidation of sensitive benzylic alcohols with chemoselectivity controlled using DMSO as the solvent

“…Our method can also be applied to 1-phenylallyl alcohols 6 (entries [19][20][21][22][23][24], although they are less reactive in oxidation to ketones 7, which are, on the other hand, more susceptible to over-oxidation to their benzoic acid derivatives, as especially evident at 45 °C. This tendency was demonstrated by the decreased yield of ketone 7 (see ESI S5 † for reactions performed under different conditions).…”

“…However, most of them use stoichiometric amounts of Cr( vi ) or other metal-based reagents. 17 Alternatively, oxidation reactions using hypervalent iodine reagents 18 or photocatalytic procedures with 2-bromoanthraquinone 19 have been shown in a limited number of examples. Very recently, the most effective and general procedure based on N -hydroxy-tetrafluorophtalimide (TFNHPI) as an electrochemical mediator and tert -butylhydroperoxide as a stoichiometric oxidizing agent has been developed.…”

Electrochemically Mediated Oxidation of Sensitive Propargylic Benzylic Alcohols

“…Despite this body of work, many thermal oxidations of organic compounds remain a challenge. Several recent synthetic efforts make this challenge plain, with propargylic benzylic alcohol substrates undergoing oxidation via typical thermal protocols [Jones’ reagent, , manganese­(IV) oxide, Dess–Martin periodinane, or photochemical processes with low efficiency (Scheme )]. More electron-deficient substrates such as 4 are particularly intransigent.…”