Wuheng Dong

Combining Visible-Light-Photoredox and Lewis Acid Catalysis for the Synthesis of Indolizino[1,2-b]quinolin-9(11H)-ones and Irinotecan Precursor

One-step construction of substituted indolizino[1,2-b]quinolin-9(11H)-ones was achieved by combining visible-light-photoredox and Lewis acid catalysis for an intramolecular Povarov cycloaddition reaction under mild conditions. In this catalytic process, the visible-light-promoted dehydrogenation protocol of tetrahydroquinolines constitutes the key procedure. Moreover, this method can be applied to the formal synthesis of the precursor of irinotecan, which exhibited good anticancer activities.

Visible light-induced aerobic C–N bond activation: a photocatalytic strategy for the preparation of 2-arylpyridines and 2-arylquinolines

An efficient method for accessing arylpyridines and arylquinolines via visible light-induced aerobic C–N bond activation is described. The applicability of different kinds of simple ketones, easily available amines, and the use of air as the sole oxidant make this transformation very attractive.

Visible Light-Induced Radical Rearrangement to Construct C–C Bonds via an Intramolecular Aryl Migration/Desulfonylation Process

A highly efficient intramolecular selective aryl migration/desulfonylation of 2-bromo-N-aryl-N-(arenesulfonyl)amide via visible light-induced photoredox catalysis has been accomplished. This approach allows for the construction of a variety of multisubstituted N,2-diarylacetamide under mild reaction conditions.

Visible-light induced tandem radical cyanomethylation and cyclization of N-aryl acrylamides: access to cyanomethylated oxindoles

A visible-light induced cyanomethylation of N-aryl acrylamides with bromoacetonitrile followed by intramolecular cyclization has been explored. This transformation exhibits a wide substrate scope and significant functional group tolerance, providing a facile synthetic approach and highly efficient access to cyanomethylated oxindoles.

Visible-Light-Induced Radical Cascade Cyclization: Synthesis of the ABCD Ring Cores of Camptothecins

A new strategy for constructing indolizino[1,2-b]quinolin-9(11H)-ones (ring cores of camptothecins) from readily available isocyanoarenes and N-(alkyl-2-yn-1-yl)pyridin-2(1H)-ones has been developed through a visible-light-induced radical cascade cyclization process. The reaction proceeds under mild conditions with fair to excellent yields. The easy introduction of substituents for both reactants and the broad functional group tolerance of the reaction make it a straightforward route to the cores of the marketed camptothecins and their derivatives.

Synthesis of 3-CF2-Containing Chromones via a Visible-Light-Induced Radical Cascade Reaction of o-Hydroxyaryl Enaminones

A general and efficient visible-light-induced CF2 radical-based cascade reaction of o-hydroxyaryl enaminones has been described. This protocol afforded the corresponding functionalized 3-CF2-containing chromones in generally good yields under mild reaction conditions. The use of NaHSO3, which has both basicity and reducibility, efficiently suppressed the formation of two byproducts, 4H-chromen-4-one and 3-bromo-4H-chromen-4-one.

Visible-Light-Induced Intermolecular Dearomative Cyclization of 2-Bromo-1,3-dicarbonyl Compounds and Alkynes: Synthesis of Spiro[4.5]deca-1,6,9-trien-8-ones

A visible-light-induced photocatalytic intermolecular dearomative cyclization of 2-bromo-1,3-dicarbonyl compounds and alkynes afforded biologically important spirocarbocycle structures in moderate to good yields via a 5-exo-dig radical cyclization under mild reaction conditions. A 5.0 mmol scale dearomatization reaction proceeded smoothly with 95% yield even when the catalyst loading was reduced to 0.1 mol %, suggesting that this method was suitable for large-scale synthesis.

Merging Visible-Light Photoredox and Lewis Acid Catalysis for the Intramolecular Aza-Diels-Alder Reaction: Synthesis of Substituted Chromeno[4,3-b]quinolines and [1,6]Naphthyridines

Substituted chromeno[4,3‐b]quinolines and [1,6]naphthyridines were achieved by tandem intramolecular aza‐Diels–Alder reaction using a strategy of combination of visible‐light photoredox and Lewis‐acid‐catalysis. This intramolecular aza‐Diels–Alder cycloaddition took place between the in situ generated benzylidene anilines derived from arylamines and salicylaldehyde or 2‐aminoaryl aldehydes bearing a tethered alkene partner, followed by oxidative aromatization to give the target products. The study on the oxidative aromatization step revealed that it is much faster than the cyclization step; both the combination of imine and Lewis acid, and the combination of photocatalyst and Lewis acid under aerobic condition with the irradiation of visible light are efficient to achieve the transformation. This method provided a new access to the synthesis of important heterocycles under mild reaction conditions.