Search

The construction of an aryl ketone structural unit by means of catalytic carbon-carbon coupling reactions represents the state-of-the-art in organic chemistry. Herein we achieved the direct deoxygenative ketone synthesis in aqueous solution from readily available aromatic carboxylic acids and alkenes, affording structurally diverse ketones in moderate to good yields. Visible-light photoredox catalysis enables the direct deoxygenation of acids as acyl sources with triphenylphosphine and represents a distinct perspective on activation. The synthetic robustness is supported by the late-stage modification of several pharmaceutical compounds and complex molecules. This ketone synthetic strategy is further applied to the synthesis of the drug zolpidem in three steps with 50% total yield and a concise construction of cyclophane-braced 18-20 membered macrocycloketones. It represents not only the advancement for the streamlined synthesis of aromatic ketones from feedstock chemicals, but also a photoredox radical activation mode beyond the redox potential of carboxylic acids.

The involvement of manganese radical for halogen atom transfer (XAT) reactions has been esteemed as one reliable method but encountered with limited catalytic models. In this paper, a novel bimetallic relay catalysis of Mn2(CO)10 and cobaloxime has been developed for divergent dehydrogenative difluoroalkylation of alkenes using commercially available difluoroalkyl bromides. A wide range of structurally diverse terminal, cyclic and internal alkenes as well as tetrasubstituted alkenes are found to be good coupling partners to deliver difluoroalkylated allylic products and difluoromethylated cyclic products, accompanied with the production of H2 as the by‐product. This bimetallic relay strategy features broad substrate scope, mild reaction conditions and excellent functional group compatibility. Its success represents an important step‐forward to expedite the construction of a rich library of difluoroalkylated products. [ABSTRACT FROM AUTHOR]

Activated alkyl halides have been extensively explored to generate alkyl radicals with Ru‐ and Ir‐ photocatalysts for 1,2‐difunctionalization of alkenes, but unactivated alkyl bromides remain challenging substrates due to their strong reduction potential. Here we report a three‐component 1,2‐difunctionalization reaction of alkenes, unactivated alkyl bromides and nucleophiles (e.g. amines and indoles) using a trinuclear gold catalyst [Au3(tppm)2](OTf)3. It can achieve the 1,2‐aminoalkylation and 1,2‐alkylarylation readily. This protocol has a broad reaction scope and excellent functional group compatibility (>100 examples with up to 96 % yield). It also affords a robust formal [2+2+1] cyclization strategy for the concise construction of pyrrolidine skeletons under mild reaction conditions. Mechanistic studies support an inner‐sphere single electron transfer pathway for the successful cleavage of inert C−Br bonds. [ABSTRACT FROM AUTHOR]

The synthesis of all-carbon tetrasubstituted olefins under mild reaction conditions is challenging because of the inevitable issues including significant steric hindrance and the uncontrolled Z/E stereoselectivity. In this paper, we report the synthesis of all-carbon tetrasubstituted alkenes from readily available carboxylic acids and alkenyl triflates with the synergistic catalysis of cyclo-octa-1,5-diene(tetramethyl-1,4-benzoquinone)nickel and visible light under an air atmosphere, thus avoiding the need for a glovebox or a Schlenk line. A wide range of aromatic carboxylic acids and cyclic and acyclic alkenyl triflates undergo the C-C coupling process smoothly, forming structurally diverse alkenes stereospecifically in moderate to good yields. The practicality of the method is further illustrated by the late-stage modification of complex molecules, the one pot synthesis and gram-scale applications. This is an important step towards the valuable utilization of carboxylic acids, and it also simplifies the experimental operation of metallophotoredox catalysis with moisture sensitive nickel(0) catalysis. Tetrasubstituted olefins have been explored as chemical synthons and can sometime have useful photophysical properties, but are sometimes difficult to synthesize with high selectivity in mild conditions. Here the authors present a method to make tetrasubstituted olefins via dual photo- and nickel catalysis, without the need for an inert atmosphere. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The arylethylamine framework is a prevalent motif in a great range of biologically important organic compounds. One intractable task for frontline drug discovery is to find structurally new medicine candidates instead of opioid, based on the construction of a rich chemical space of arylethylamine motif. In this report, a practical protocol for the synthesis of arylethylamine functionality common in pharmaceutical chemicals has been developed. It proceeds by Mn‐catalyzed anti‐Markovnikov hydroarylation of electron‐rich enamides under mild conditions without the use of ligands. In spite of mismatched electronic effects during the manganese‐mediated migratory insertion process, both terminal and internal enamides can be regioselectively hydroarylated with various aryl boronic acids in 15 min. Also, the successful hydroalkenylation of enamides with alkenyl boronic acids in air atmosphere affords an elegant route to synthetically useful β‐alkenylated amines in satisfactory yields. The synthetic robustness and practicality of the reaction reveal its simple operation, short reaction time, viability on a gram‐scale and its value in late‐stage modification of complex molecules. [ABSTRACT FROM AUTHOR]

We report a general, practical and scalable hydroacylation reaction of ethylene with aromatic carboxylic acids with the synergistic combination of nickel and photoredox catalysis. Under ambient temperature and pressure, feedstock chemicals such as ethylene can be converted into high-value-added aromatic ketones in moderate to good yields (up to 92%) with reaction time of 2 – 6 hours. [ABSTRACT FROM AUTHOR]

An efficient photoredox radical borylation of electron-deficient Morita–Baylis–Hillman type alkenes is achieved to afford multi-functionalized allylic boranes. The reaction demonstrates a wide substrate scope and showcases excellent functional group tolerance. It has advantages over the traditional ionic hydroboration methods in the construction of allylic boranes in terms of simple operation, mild conditions, and step-economy. [ABSTRACT FROM AUTHOR]

In this Communication, we report an unprecedented β‐regioselective radical inverse hydroboration (compared with ionic hydroboration) of α,β‐unsaturated amides with NHC‐BH3 enabled by photoredox catalysis. Density functional theory (DFT) calculations show that the unique photoredox cycle is a key factor to control the β‐regioselective radical hydroboration, by lowering the energy barrier in comparison with other pathways. This protocol provides a general and convenient route to construct a wide range of structurally diverse β‐borylated amides in synthetically useful yields under mild conditions. [ABSTRACT FROM AUTHOR]

Alkenes, Difunctionalization, Gold Catalysis, Photoredox Catalysis, Radical In their Research Article (e202305121), Jin Xie and co-workers overcome the inherent redox potential limit of alkyl bromides and achieve 1,2-aminoalkylation and 1,2-alkylarylation of different alkenes by using the inner single electron transfer mechanism of an excited trinuclear gold catalyst. Keywords: Alkenes; Difunctionalization; Gold Catalysis; Photoredox Catalysis; Radical EN Alkenes Difunctionalization Gold Catalysis Photoredox Catalysis Radical 1 1 1 08/17/23 20230821 NES 230821 B Inert alkyl bromides b are rarely used in photoinduced 1,2-difunctionalization of alkenes due to their strong reduction potential and bond dissociation energy. [Extracted from the article]

Keywords: Alkenes; Difunctionalization; Gold Catalysis; Photoredox Catalysis; Radical EN Alkenes Difunctionalization Gold Catalysis Photoredox Catalysis Radical 1 1 1 08/21/23 20230821 NES 230821 B Inert alkyl bromides b are rarely used in photoinduced 1,2-difunctionalization of alkenes due to their strong reduction potential and bond dissociation energy. In their Research Article (e202305121), Jin Xie and co-workers overcome the inherent redox potential limit of alkyl bromides and achieve 1,2-aminoalkylation and 1,2-alkylarylation of different alkenes by using the inner single electron transfer mechanism of an excited trinuclear gold catalyst. Inside Back Cover: Trinuclear Gold-Catalyzed 1,2-Difunctionalization of Alkenes (Angew. [Extracted from the article]

Trifluoromethylation/arylation: N‐aryl acrylamides undergo visible‐light‐induced tandem trifluoromethylation/arylation in the presence of a ruthenium photocatalyst with Togni's reagent as the CF3 source (see scheme). This reaction serves as a powerful and ecofriendly synthetic method for the preparation of a variety of CF3‐containing oxindoles bearing a quaternary carbon center. [ABSTRACT FROM AUTHOR]

A cascade radical oxidative difunctionalization of alkynoates with simple ethers for the construction of tri-substituted olefins is developed. The reaction undergoes cascade radical addition to C–C triple bond, 1,4-aryl migration, and decarboxylation to deliver a variety of difunctionalized alkenes in moderate to good yields. This procedure also represents a promising strategy for the direct functionalization of the α-Csp 3 -H bonds in ether derivatives. [ABSTRACT FROM AUTHOR]

The described method represents the first visible light induced tandem trifluoromethylation/arylation of electron-withdrawing alkenes. [ABSTRACT FROM AUTHOR]