Para-Selective Cyanation of Arenes by H-Bonded Template.

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work, we demonstrate the para-selective introduction of versatile nitrile moiety, enabled by a detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias.

Photocatalyzed borylation using water-soluble quantum dots.

The synthesis of arylboronates by Sandmeyer-type reactions in the presence of water still remains a significant challenge. Herein, we report the use of water-soluble MPA-capped quantum dot (QD) photocatalysts for the borylation of diazonium salts in the presence of water. A biphasic system under mild acidic conditions remains critical to prevent decomposition and competitive disulphide bond formation.

H-bonded reusable template assisted para-selective ketonisation using soft electrophilic vinyl ethers.

In nature, enzymatic pathways generate C-C(O) bonds in a site-selective fashion. Synthetically, C-C(O) bonds are synthesised in organometallic reactions using prefunctionalized substrate materials. Electrophilic routes are largely limited to electron-rich systems, non-polar medium, and multiple product formations with a limited scope of general application.

Fe-polyaniline composite nanofiber catalyst for chemoselective hydrolysis of oxime.

A facile chemoselective one-pot strategy for the deprotection of oxime has been developed using Fe-polyaniline composite nanofiber (Fe-PANI), as a catalyst. Nano material based Fe-PANI catalyst has been synthesized via in-situ polymerization of ANI monomer and followed by reductive deposition of Fe onto PANI matrix. The catalyst was characterized by FE-SEM, HR-TEM, BET, XRD, ATR-FTIR, XPS and VSM techniques.

Experimental and Computational Exploration of para-Selective Silylation with a Hydrogen-Bonded Template.

The regioselective conversion of C-H bonds into C-Si bonds is extremely important owing to the natural abundance and non-toxicity of silicon. Classical silylation reactions often suffer from poor functional group compatibility, low atom economy, and insufficient regioselectivity. Herein, we disclose a template-assisted method for the regioselective para silylation of toluene derivatives.

Directing group assisted -hydroxylation by C-H activation.

-Hydroxylated cores are ubiquitous in natural products. Herein, we disclose the first template assisted hydroxylation reaction. Experimental and studies helped us to gain valuable mechanistic insights, including the role of the hexafluoroisopropanol (HFIP) solvent, during C-H hydroxylation.

Remote para-C-H Functionalization of Arenes by a D-Shaped Biphenyl Template-Based Assembly.

Site-selective C-H functionalization has emerged as an efficient tool in simplifying the synthesis of complex molecules. Most often, directing group (DG)-assisted metallacycle formation serves as an efficient strategy to ensure promising regioselectivity. A wide variety of ortho- and meta-C-H functionalizations stand as examples in this regard.

Palladium(II)-Catalyzed meta-C-H Olefination: Constructing Multisubstituted Arenes through Homo-Diolefination and Sequential Hetero-Diolefination.

Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium-catalyzed synthesis of divinylbenzenes by meta-C-H olefination of sulfone-based arenes. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods.

Meta-selective arene C-H bond olefination of arylacetic acid using a nitrile-based directing group.

A nitrile-based template attached with a phenylacetic acid framework promoted meta-selective C-H bond olefination. This palladium-catalyzed protocol is applicable to a wide range of substituted phenylacetic acids and tolerates a variety of functional groups. The versatility of this operationally simple method has been demonstrated through drug diversification.

Direct synthesis of α-trifluoromethyl ketone from (hetero)arylacetylene: design, intermediate trapping, and mechanistic investigations.

Regioselective addition across the alkynes has been achieved in a silver-catalyzed protocol utilizing Langlois reagent (CF3SO2Na) and molecular O2 to access medicinally active α-trifluoromethyl ketone compounds. This method was successful in producing α-trifluoromethyl ketone in heterocyclic scaffolds, which are incompatible with earlier strategies. Experimental findings suggest a mechanism involving α-styrenyl radical intermediate and 1-methyl-2-pyrrolidinone (NMP) solvent, which leads to crystallographically characterized N-methylsuccinimide.

Synthesis of bis(heteroaryl) ketones by removal of benzylic CHR and CO groups.

A copper-catalyzed method for synthesis of diaryl ketones (Ar-CO-Ar') through removal of benzylic -CH2-, -CO-, and -CHR- groups from Ar-CO-CXR-Ar' has been discovered. A number of symmetrical and unsymmetrical heterocyclic ketones, which are usually difficult to synthesize, can be prepared in good to excellent yields. This method was applied to the synthesis of the nonsteroidal anti-inflammatory drug suprofen (47% yield over three steps).

Synthesis of (E)-nitroolefins via decarboxylative nitration using t-butylnitrite (t-BuONO) and TEMPO.

Nitroolefins are usually synthesized using the Henry reaction. Here we report an alternative metal-free decarboxylative nitration protocol for the preparation of the nitroolefins from α,β-unsaturated carboxylic acids using t-butylnitrite (t-BuONO) and TEMPO. α,β-Unsaturated carboxylic acids bearing β-aromatic and β-heteroaromatic substituents gave (E)-nitroolefins exclusively under mild conditions.