Phosphazene Superbase-Mediated Regio- and Stereoselective Iodoaminocyclization of 2-(1-Alkynyl)benzamides for the Synthesis of Isoindolin-1-ones

Metal-Free Synthesis of 4-Bromoisoquinolines through Brominative Annulation of 2-Alkynyl Arylimidate Using In Situ-Generated Transient Bromoiodane

Herein, we report the in situ-generated transient bromoiodane-mediated brominative annulation of 2-alkynyl arylimidate for the synthesis of 4-bromoisoquinolines at room temperature. Using a simple hypervalent iodine reagent PIDA as a mild oxidant and potassium bromide as the halogen source, a broad range of valuable 4-bromoisoquinolines can be synthesized in excellent yields. The reaction features readily available chemicals, mild metal-free conditions, and high functional group tolerance, providing an efficient alternative for the construction of halogenated isoquinolines.

Substrate-Dependent Stereoselective Synthesis of Pyrrolo[3,4-b]Pyridin-5-Ones and Pyridyl Isoindoline-1-Ones Using Bis(benzotriazol-1-yl) Ligand

The documented work highlighted the synthesis of bis(benzotriazol-1-yl) methane derivatives using silicomolybdic acid (SMA) and successfully implemented in the stereoselective synthesis of diverse pyrrolo[3,4-b]pyridin-5-one and pyridyl isoindolinones derivatives in one-pot. The pyridinamide precursor with diverse alkynes furnished Z-selectivity of pyrrolo[3,4-b]pyridin-5-one across exocyclic C=C bond while the various benzamides on treating with 2-ethynyl pyridine afforded (E)-pyridylisoindoline-1-ones as a major isomer. The single-crystal X-ray diffraction provides strong evidence in favor of the existence and orientation of developed compounds. The broad substrate scope, easy accessibility of substrates, high stereoselectivity, scale-up synthesis, and crystal evidence demonstrate the merits of the current decorum.

Current-Controlled Electrochemical Approach Toward Mono- and Trifluorinated Isoindolin-1-one Derivatives

An electrochemical intramolecular 5-exo-dig aza-cyclization of 2-alkynylbenzamides and subsequent nucleophilic fluorination have been developed to afford the highly selective synthesis of mono- and trifluorinated isoindolin-1-one derivatives. This work demonstrates the unique capability of synthetic electrochemistry in controlling reaction selectivity through the applied electrolytic parameters. In addition, the obtained monofluorinated 3-methyleneisoindolin-1-one (19) displays interesting photophysical properties that are not observed in its nonfluorinated analog.

A deconstruction-reconstruction strategy to access 1-naphthol derivatives: application to the synthesis of aristolactam scaffolds

A deconstruction-reconstruction strategy for the synthesis of multisubstituted polycyclic aromatic hydrocarbons (PAHs) is delineated herein. The deconstruction step enables the synthesis of o-cyanomethylaroyl fluorides that are bifunctional substrates holding both a pro-nucleophile and an electrophile. The construction step involves a formal [4 + 2] benzannulation using o-cyanomethylaroyl fluorides and active methylenes. The utility of this synthetic method is also demonstrated by the synthesis of a tetracyclic aristolactam derivative.

Unexpected Cascade Sequence Forming the C(sp3)-N/C(sp2)-C(sp2) Bond: Direct Access to γ-Lactam-Fused Pyridones with Anticancer Activity

An unexpected Ugi cascade reaction was developed for the facile construction of γ-lactam-fused pyridone derivatives with high tolerance of substrates. A C(sp3)-N bond and a C(sp2)-C(sp2) bond were formed together, accompanied by a chromone ring-opening in Ugi adducts, under the basic conditions without any metal catalyst for the whole process. Screening data of several difficult-to-inhibit cancer cell lines demonstrated that 7l displayed a high cytotoxicity against HCT116 cells (IC50 = 5.59 ± 0.78 μM). Taken together, our findings revealed new insights into the molecular mechanisms underlying compound 7l and provided potential usage of this scaffold for cancer therapeutics.

Copper-Catalyzed Asymmetric Hydroboration Reaction of Novel Methylene Isoindolinone Compounds through Microwave Irradiation and Their Antileishmanial and Antitoxoplasma Activities

The aim of this study was devoted into molecular docking calculations to discover the potential antileishmania and antitoxoplasma activities of newly synthesized compounds obtained by applying a practical and simple method under microwave irradiation. All these compounds were tested in vitro for their biological activity against Leishmania major promastigotes, amastigotes, and Toxoplasma gondii tachyzoites. Compounds 2a, 5a, and 5e were the most active against both L. major promastigotes and amastigotes, with IC₅₀ values of less than 0.4 μM mL^-1. Compounds 2c, 2e, 2h, and 5d had a strong antitoxoplasma activity of less than 2.1 μM mL^-1 against T. gondii. We can conclude that aromatic methyleneisoindolinones are potently active against both L. major and T. gondii. Further studies for mode of action evaluation are recommended. Compounds 5c and 5b are the best drug candidates for antileishmania and antitoxoplasma due to their SI values being over 13. The docking studies of compounds 2a-h and 5a-e against pteridine reductase 1 and T. gondii enoyl acyl carrier protein reductase reveal that compound 5e may be an effective antileishmanial and antitoxoplasma drug discovery initiative.

The organocatalytic synthesis of perfluorophenylsulfides via the thiolation of trimethyl(perfluorophenyl)silanes and thiosulfonates

The organic superbase t-Bu-P₄-catalyzed direct thiolation of trimethyl(perfluorophenyl)silanes and thiosulfonates was developed. Yields of perfluorophenylsulfides of up to 97% under catalysis of 5 mol% t-Bu-P₄ were achieved. This method was shown to provide an efficient way to construct the perfluorophenyl-sulfur bond under mild metal-free reaction conditions.

Iron-catalyzed stereoselective haloamidation of amide-tethered alkynes

In this work, by using N-methoxybenzamides as efficient acyl nitrene precursors, an iron-catalyzed formal cis-haloamidation of alkyne is reported. Without assistance of additives, the reaction worked well in the presence of 50 mol% FeCl3 or FeBr3, leading to a series of chloro/bromo-containing isoindolin-5-ones with high efficiency and wide reaction scope. In the reaction, the iron-facilitated haloamidation proceeds through a halo anion-participating concerted [3+2] cyclization to release the final products. The key intermediate ferric acyl nitrene A is generated in situ from a formal removal of MeOH.

Ring Opening/Site Selective Cleavage in N-Acyl Glutarimide to Synthesize Primary Amides

A LiOH-promoted hydrolysis selective C-N cleavage of twisted N-acyl glutarimide for the synthesis of primary amides under mild conditions has been developed. The reaction is triggered by a ring opening of glutarimide followed by C-N cleavage to afford primary amides using 2 equiv of LiOH as the base at room temperature. The efficacy of the reactions was considered and administrated for various aryl and alkyl substituents in good yield with high selectivity. Moreover, gram-scale synthesis of primary amides using a continuous flow method was achieved. It is noted that our new methodology can apply under both batch and flow conditions for synthetic and industrial applications.

A Serendipitous One-Pot Cyanation/Hydrolysis/Enamide Formation: Direct Access to 3-Methyleneisoindolin-1-ones

A direct, one-pot conversion of 2'-haloacetophenones to 3-methyleneisoindolin-1-one scaffolds using CuCN as the sole reagent without the need for moisture-free or anaerobic conditions is reported. This serendipitously discovered transformation with a broad substrate scope provides a significantly different route towards these important scaffolds. The scope of the method has also been further extended towards the synthesis of three special scaffolds, which are analogous to various bio-active drugs.

Organocatalytic aminocarbonylation of α,β-unsaturated ketones with N,N-dimethyl carbamoylsilane

Schwesinger's superbase can efficiently activate the Si–CONMe₂ bond and initiate the aminocarbonylation of α,β-unsaturated ketones and N,N-dimethyl carbamoylsilane.