Low‐Voltage‐Driven Electrochemical Aerobic Oxygenation with Flavin Catalysis: Chemoselective Synthesis of Sulfoxides from Sulfides

Abstract

The chemoselective electrochemical oxygenation of sulfides to sulfoxides is performed using a biomimetic flavin catalyst that enables the activation of molecular oxygen under a low cathode potential. Diverse functional groups, including alcohols, ketones, aldehydes, cyclopropane, carboxylic acids, pyridine, alkenes, and alkynes, are well tolerated under low‐voltage electrolytic conditions.

Aerobic oxidative synthesis of benzimidazoles by flavin photocatalysis

“…The radical flavin FlH˙ may also undergo a disproportionation reaction with another FlH˙ to form Fl and FlH 2 (Scheme 4C). 22 As suggested by the control experiment in Scheme 3C, the subsequent dehydrogenative aromatisation from 10 to 3 occurs under O 2 , while the flavin catalyst slightly enhanced the process. 23 FlH 2 is also produced by the dehydrogenative aromatisation of 10 into 3 .…”

Aerobic cross-dehydrogenative coupling of toluenes and o-phenylenediamines by flavin photocatalysis for the facile synthesis of benzimidazoles

“…The radical flavin Fl rad generated via single-electron transfer from 1 undergoes disproportionation with another Fl rad to form Fl and the reduced flavin FlH 2 that received two electrons. 21 The reduced FlH 2 is also generated by the dehydrogenative aromatisation of 10 to 3 , as mentioned above. Reduced flavins such as FlH 2 possess unique O 2 -activation ability, and thus react with air (O 2 ) to give the initial Fl and hydrogen peroxide.…”

Metalloligand Hybrid Polyoxometalates for Efficient Selective Photocatalytic Oxidation of Sulfides to Sulfoxides under Visible-Light Irradiation

“…Sulfoxides are important organic compounds and are widely used in medical and biological industries. − Oxidation of sulfides is the simplest and most common method for the synthesis of sulfoxides. , In particular, the photocatalytic oxidation of sulfides with O 2 under light irradiation displays the advantages of a simple process, environmental friendliness, and mild reaction conditions, such as room temperature (RT) and atmospheric pressure, and has been extensively investigated for replacing conventional thermal oxidation synthesis methods. , In recent years, a variety of photocatalysts have been developed to carry out this reaction. Although they exhibit good photocatalytic activity, there are still some problems such as long reaction times, unclear structures, and difficulties in catalyst recovery. − Therefore, there is a need to develop reusable, highly active photocatalysts for the selective oxidation of sulfides under mild conditions to prepare sulfoxides.…”

“…1−4 Oxidation of sulfides is the simplest and most common method for the synthesis of sulfoxides. 5,6 In particular, the photocatalytic oxidation of sulfides with O 2 under light irradiation displays the advantages of a simple process, environmental friendliness, and mild reaction conditions, such as room temperature (RT) and atmospheric pressure, and has been extensively investigated for replacing conventional thermal oxidation synthesis methods. 7,8 In recent years, a variety of photocatalysts have been developed to carry out this reaction.…”