9,10-Dihydroanthracene auto-photooxidation efficiently triggered photo-catalytic oxidation of organic compounds by molecular oxygen under visible light

KuQuinone as a Highly Stable and Reusable Organic Photocatalyst in Selective Oxidation of Thioethers to Sulfoxides

“…The effect of singlet oxygen scavengers (i.e., DABCO: 1,4diazobicyclo[2.2.2]octane and sodium azide), superoxide anion scavengers (benzoquinone and N-tert-butyl-1-phenylmethani- mine oxide), radical scavenger (TEMPO: 2,2,6,6-tetramethylpiperidin-1-yloxyl), and radical cation scavenger (1,4-dimethoxybenzene) has been investigated in the standard reaction conditions (Table 1, entry 7), in the presence of 5 equiv of the quencher (Figure S4). 32,34,40,41 Thioanisole was used as the model substrate, and reaction progress was monitored by GC-MS. Thioanisole oxidation has been also performed in the presence of 1 equiv of diphenyl sulfoxide, because the oxidation of the latter is usually related with the presence of a nucleophilic persulfoxide intermediate, generated through the energy transfer pathway. 62 Experimental data suggested that KuQ-promoted photooxidation of thioethers did not occur through 1 O 2 formation (as in Scheme 2, pathway a), because of the following:…”

“…Therefore, several metal-based catalysts (such as Zr-based metal organic frameworks, , dye sensitized TiO 2 , Pt/BiVO 4 , visible-light-responsive decavanadate, photoactive Pt­(II) and uranyl complexes and Ru­(II)–Cu­(II) dinuclear metal complexes) oreven more interestingmetal-free organic photocatalysts have been explored. Specifically, anthraquinone, , dihydroanthracene, flavin and alloxazine derivatives, , BODIPYs, , perylene diimmide, and thioxantones , have been adopted in thioether oxidation, with promising results.…”

Visible Light-Induced Aerobic Oxidative Dehydrogenation of C–N/C–O to C=N/C=O Bonds Using Metal-Free Photocatalysts: Recent Developments

“…Cascade transformation of racemic alcohols into enantiopure amines 74 by oxidative dehydrogenation catalyzed by 73 and enantioselective transamination. 9,10-dihydroanthracene (10 mol%) promoted the photo-oxidation of the benzyl alcohol, hexanol, cyclohexanol and furfuryl alcohol to their respective aldehydes and ketones in very good yields, using pure O2 and irradiated with a tungsten-bromine lamp [170]. Another observed product from primary alcohols was the corresponding carboxylic acid.…”

“…This group includes a tetrazine-based catalyst (pytz, 75) using two methodologies [171], a dicyanopyrazine-derived chromophore (DPZ, 76) used in cooperation with N-hydroxysuccinimide (NHS) and dibenzyl phosphoric acid (DBPA) [172], and an iminoquinone-based catalyst (PA, 77) [173], enabling all of them to obtain aldehydes and ketones 69 from alcohols in moderate to excellent yields (Figure 21). 9,10-dihydroanthracene (10 mol%) promoted the photo-oxidation of the benzyl alcohol, hexanol, cyclohexanol and furfuryl alcohol to their respective aldehydes and ketones in very good yields, using pure O 2 and irradiated with a tungsten-bromine lamp [170]. Another observed product from primary alcohols was the corresponding carboxylic acid.…”