Yingqian Duan

Cascade Photoredox/Iodide Catalysis: Access to Difluoro-γ-lactams via Aminodifluoroalkylation of Alkenes

The novel cascade photoredox/iodide catalytic system enables the alkene to serve as a radical acceptor capable of achieving aminodifluoroalkylation of alkenes. Cheap iodide salts play a vital role in this reaction, which could tune carbocation reactivity through reversible C-I bond formation for controlling reaction selectivity, and a series of competitive reactions are completely eliminated in the presence of multiple reactivity pathways. The present dual catalytic protocol affords a very convenient method for direct synthesis of various difluoro-γ-lactams from simple and readily available starting materials under mild reaction conditions.

Relay Visible-Light Photoredox Catalysis: Synthesis of Pyrazole Derivatives via Formal [4 + 1] Annulation and Aromatization

A relay visible-light photoredox catalysis strategy has been accomplished. Three successive photoredox cycles (one oxidative quenching cycle and two reductive quenching cycles) are engaged in a single reaction with one photocatalyst. This strategy enables formal [4 + 1] annulation of hydrazones with 2-bromo-1,3-dicarbonyl compounds, which functionalizes three C-H bonds of hydrazones. This method affords rapid access to a complex and biologically important pyrazole scaffold in a step-economical manner with high efficiency under mild conditions.

Visible-light-induced three-component 1,2-difluoroalkylarylation of styrenes with α-carbonyl difluoroalkyl bromides and indoles

A novel visible light photoredox catalysis three-component 1,2-difluoroalkylarylation of styrenes was disclosed, and two new C–C bonds were generated in a single step through regioselective incorporation of a CF2 group and a variety of indoles to CC bonds. The well-designed photoredox system achieved the synthesis of a series of difluoro-containing indole derivatives with mild conditions and a broad substrate scope.

The direct decarboxylative allylation of N-arylglycine derivatives by photoredox catalysis

The direct decarboxylative allylation of N-arylglycine derivatives has been accomplished via visible-light photoredox catalysis. With the substrates of N-aryl glycine derivatives and allylsulfone, a series of allylation products by a redox-neutral process were readily synthesized in good yields under mild conditions. The further utility of this allylation reaction has also been evaluated for valuable structural motifs.