Muliang Zhang

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.

Photoredox-Catalyzed Hydroacylation of Olefins Employing Carboxylic Acids and Hydrosilanes

A hydroacylation reaction of alkenes has been achieved employing readily available carboxylic acids as the acyl source and hydrosilanes as a hydrogen source via photoredox catalysis. The combination of both single electron transfer and hydrogen atom transfer steps has dramatically expanded new applications of carboxylic acids in organic synthesis. The protocol also features extremely mild conditions, broad substrate scope, and good functional group tolerance, affording a novel and convenient approach to hydroacylation of alkenes.

Domino-Fluorination–Protodefluorination Enables Decarboxylative Cross-Coupling of α-Oxocarboxylic Acids with Styrene via Photoredox Catalysis

Domino-fluorination-protodefluorination decarboxylative cross-coupling of α-keto acids with styrene has been developed via photoredox catalysis. The critical part of this strategy is the formation of the carbon-fluorine (C-F) bond by the capture of a carbon-centered radical intermediate, which will overcome side reactions during the styrene radical functionalization process. Experimental studies have provided evidence indicating a domino-fluorination-protodefluorination pathway with α-keto acid initiating the photoredox cycle. The present catalytic protocol also affords a novel approach for the construction of α,β-unsaturated ketones 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.

Photoredox-Catalyzed Deoxygenative Intramolecular Acylation of Biarylcarboxylic Acids: Access to Fluorenones

An efficient deoxygenative radical cyclization reaction has been reported for the synthesis of fluorenones by employing various biarylcarboxylic acids via photoredox catalysis. Attractive features of this process include generation of acyl radical, which quickly underdone intramolecular radical cyclization. This method marks the first photocatalytic intramolecular acyl radical coupling for constructing carbon-carbon bond, which further synthesizes the valuable fluorenone products with mild conditions, good yields, and good functional-group compatibility.

Photoredox and cobalt co-catalyzed C(sp2)–H functionalization/C–O bond formation for synthesis of lactones under oxidant- and acceptor-free conditions

A practical photoredox and cobalt co-catalyzed C(sp2)–H functionalization/C–O bond formation is described herein, with dihydrogen as the only by-product. A variety of lactone products can be successfully constructed under oxidant- and acceptor-free conditions with good functional group tolerance and high yield. This protocol also provides a facile route to remote hydroxylated arenes and chromene.