Two-step cyanomethylation protocol: convenient access to functionalized aryl- and heteroarylacetonitriles

Palladium-Catalyzed Cyclization/Alkenylation of Ynone Oximes with Vinylsilanes for the Assembly of Isoxazolyl Vinylsilanes

A palladium-catalyzed cascade cyclization/alkenylation for the assembly of synthetically valuable isoxazolyl vinylsilane derivative has been accomplished. Easily accessible ynone oximes, and available vinylsilane agents were used as the reaction starting materials This protocol features broad substrate scope, good functional group tolerance, and good step- and atom-economy. Remarkably, this approach provides a new approach for the construction of structurally diverse isoxazolyl-containing vinylsilanes with high molecular complexity, showing a promising application in synthetic and pharmaceutical chemistry.

Boron Lewis Acid Catalysis Enables the Direct Cyanation of Benzyl Alcohols by Means of Isonitrile as Cyanide Source

The development of an efficient and straightforward method for cyanation of alcohols is of great value. However, the cyanation of alcohols always requires toxic cyanide sources. Herein, an unprecedented synthetic application of an isonitrile as a safer cyanide source in B(C₆F₅)₃-catalyzed direct cyanation of alcohols is reported. With this approach, a wide range of valuable α-aryl nitriles was synthesized in good to excellent yields (up to 98%). The reaction can be scaled up and the practicability of this approach is further manifested in the synthesis of an anti-inflammatory drug, naproxen. Moreover, experimental studies were performed to illustrate the reaction mechanism.

Rapid and Simple Access to α-(Hetero)arylacetonitriles from Gem-Difluoroalkenes

A scalable cyanation of gem-difluoroalkenes to (hetero)arylacetonitrile derivatives was developed. This strategy features mild reaction conditions, excellent yields, wide substrate scope, and broad functional group tolerance. Significantly, in this reaction, aqueous ammonia offers a "N" source for the "CN" reagent and entirely avoids the use of toxic cyanating reagents or metal catalysis. Hence, we provide a green and alternative method for the synthesis of arylacetonitriles.

Assembly of α-(Hetero)aryl Nitriles via Copper-Catalyzed Coupling Reactions with (Hetero)aryl Chlorides and Bromides

α-(Hetero)aryl nitriles are important structural motifs for pharmaceutical design. The known methods for direct synthesis of these compounds via coupling with (hetero)aryl halides suffer from narrow reaction scope. Herein, we report that the combination of copper salts and oxalic diamides enables the coupling of a variety of (hetero)aryl halides (Cl, Br) and ethyl cyanoacetate under mild conditions, affording α-(hetero)arylacetonitriles via one-pot decarboxylation. Additionally, the CuBr/oxalic diamide catalyzed coupling of (hetero)aryl bromides with α-alkyl-substituted ethyl cyanoacetates proceeds smoothly at 60 °C, leading to the formation of α-alkyl (hetero)arylacetonitriles after decarboxylation. The method features a general substrate scope and is compatible with various functionalities and heteroaryls.

Radical cyanomethylation via vinyl azide cascade-fragmentation

Herein, a novel methodology for radical cyanomethylation is described. The process is initiated by radical addition to the vinyl azide reagent 3-azido-2-methylbut-3-en-2-ol which triggers a cascade-fragmentation mechanism driven by the loss of dinitrogen and the stabilised 2-hydroxypropyl radical, ultimately effecting cyanomethylation. Cyanomethyl groups can be efficiently introduced into a range of substrates via trapping of α-carbonyl, heterobenzylic, alkyl, sulfonyl and aryl radicals, generated from a variety of functional groups under both photoredox catalysis and non-catalytic conditions. The value of this approach is exemplified by the late-stage cyanomethylation of pharmaceuticals.

Structure-Based Design of MptpB Inhibitors That Reduce Multidrug-Resistant Mycobacterium tuberculosis Survival and Infection Burden in Vivo

Mycobacterium tuberculosis protein-tyrosine-phosphatase B (MptpB) is a secreted virulence factor that subverts antimicrobial activity in the host. We report here the structure-based design of selective MptpB inhibitors that reduce survival of multidrug-resistant tuberculosis strains in macrophages and enhance killing efficacy by first-line antibiotics. Monotherapy with an orally bioavailable MptpB inhibitor reduces infection burden in acute and chronic guinea pig models and improves the overall pathology. Our findings provide a new paradigm for tuberculosis treatment.

Photoredox Cyanomethylation of Indoles: Catalyst Modification and Mechanism

The direct cyanomethylation of indoles at the 2- or 3-position was achieved via photoredox catalysis. The versatile nitrile synthon is introduced as a radical generated from bromoacetonitrile, a photocatalyst, and blue LED as a light source. The mechanism of the reaction is explored by determination of the Stern-Volmer quenching constants. By combining photophysical data and mass spectrometry to follow the catalyst decomposition, the catalyst ligands were tuned to enable synthetically useful yields of radical coupling products. A range of indole substrates with alkyl, aryl, halogen, ester, and ether functional groups participate in the reaction, affording products in 16-90% yields. The reaction allows the rapid construction of synthetically useful cyanomethylindoles, products that otherwise require several synthetic steps.

Reductive ortho C–H cyanoalkylation of aryl(heteroaryl) sulfoxides: a general approach to α-aryl(heteroaryl) nitriles

A catalyst-free low-temperature cyanoalkylation has been developed as a general protocol for the synthesis of α-aryl(heteroaryl) nitriles.

Palladium-catalyzed ligand-promoted site-selective cyanomethylation of unactivated C(sp3)-H bonds with acetonitrile

The direct coupling of unactivated sp³ C–H bonds in aliphatic amides with acetonitrile was achieved via palladium catalysis.

The direct cyanomethylation of unactivated sp³ C–H bonds of aliphatic amides was achieved via palladium catalysis assisted by a bidentate directing group with good functional group compatibility. This process represents the first example of the direct cross-coupling of sp³ C–H bonds with acetonitrile. Considering the importance of the cyano group in medicinal and synthetic organic chemistry, this reaction will find broad application in chemical research.

TEMPO-catalyzed synthesis of 5-substituted isoxazoles from propargylic ketones and TMSN3

A novel and efficient TEMPO-catalyzed synthesis of 5-substituted isoxazoles from propargylic ketones and TMSN₃via the radical mechanism process is described. A plausible reaction mechanism for this process is proposed.

Synthesis of 3,4,5-trisubstituted isoxazoles via 1,3-dipolar cycloaddition/SO2 extrusion of benzoisothiazole-2,2-dioxide-3-ylidenes with nitrile oxides

An straightforward synthesis of 3,4,5-trisubstituted isoxazole derivatives via 1,3-dipolar cycloaddtion/SO₂ extrusion of benzoisothiazole-2,2-dioxide-3-ylidenes with nitrile oxides is reported using 4 Å molecular sieves as dehydrochlorinating agent.

Synthesis of 3,4,5-Trisubstituted Isoxazoles from Morita-Baylis-Hillman Acetates by an NaNO2 /I2 -Mediated Domino Reaction

An efficient NaNO2 /I2 -mediated one-pot transformation of Morita-Baylis-Hillman (MBH) acetates into alkyl 3-nitro-5-(aryl/alkyl)isoxazole-4-carboxylates is described. In a cascade event, initial Michael addition of NaNO2 to the MBH acetate furnishes the allylnitro intermediate which undergoes I2 -catalyzed oxidative α-CH nitration of the nitromethyl subunit followed by [3+2] cycloaddition to afford the title compounds. Structural elaborations of these highly substituted isoxazoles by SN Ar reactions and hydrogenolysis allows access to useful products.

β-Ketophosphonates formation via deesterification or deamidation of cinnamyl/alkynyl carboxylates or amides with H-phosphonates

We report here an unprecedented Fe/Cu synergistically catalyzed deesterificative or deamidative oxyphosphorylation of unsaturated carboxylates or amides with H-phosphonates.

An organo-NHC catalyzed domino addition approach for the selective synthesis of 5-butynylisoxazoles and subsequent Sonogashira coupling

An organo-NHC catalysed domino addition approach for the selective synthesis of 5-butynylisoxazoles and the subsequent Sonogashira cross-coupling for the selective synthesis of corresponding internal alkynes is described.