Palladium-Catalyzed Cascade Reactions of 2-(Cyanomethoxy)chalcones with Arylboronic Acids: Selective Synthesis of Emissive Benzofuro[2,3-c]pyridines

Abstract

The Pd­(II)-catalyzed cascade reactions of 2-(cyanomethoxy)­chalcones with arylboronic acids were demonstrated, allowing the rapid construction of benzofuro­[2,3-c]­pyridine skeletons with excellent selectivity. These transformations involve the domino-style formation of C–C/C–C/C–N bonds through nitrile carbopalladation, intramolecular Michael addition, cyclization, and aromatization. This chemistry allows for the reactions of 2-(cyano­methoxy)­chalcones with thiophen-3-ylboronic acid, providing 3-aryl-1-(thiophen-3-yl)­benzo­furo­[2,3-c]­pyridines in moderate to good yields. In addition, the resulting products represent a new class of emissive fluorophores.

Palladium(II)-Catalyzed C(sp)–C(sp2) Coupling: A Direct Approach to Multi-Substituted Pyrrolo[1,2-a]pyrazines

“…SYNTHESIS0 0 3 9 -7 8 8 1 1 4 3 7 -2 1 0 X Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart 2021, 53, 2051-2056 Palladium-catalyzed synthesis of arylketones through addition of arylboronic acids to nitriles was initially developed by Lacrock's group, 15,16 and it has been exploited in novel synthetic strategies to provide functionalized heterocycles in recent years. [17][18][19][20][21] Based on our previous work, 22,23 we envisioned that 2-formylpyrroloacetonitriles might afford pyrrolo [1,2-a]pyrazine nucleus through C-C coupling with phenylboronic acid and further intramolecular cyclization. Herein, we report a novel Pd-catalyzed tandem reaction to deliver pyrrolo [1,2-a]pyrazines with easy manipulation.…”

Design and Synthesis of Fluorescent 1,3-Diaryl-β-carbolines and 1,3-Diaryl-3,4-dihydro-β-carbolines

“… 9 Due to the relative ease of synthesis and vast range of potential biological activities, the β-carboline scaffold has long been a valuable platform in drug discovery efforts. The intriguing photoluminescence properties of the β-carbolines 10 and structural analogues 11 have also elicited interest for potential applications in material chemistry, organic light-emitting diodes (OLEDs), 12 and optical sensing agents for selective quantitative analysis of chemical entities. 13 …”

“…Chen and co-workers recently described the palladium-catalyzed synthesis and photoemissive properties of several structurally related 1,3-diarylbenzofuro[2,3- c ]pyridines ( Scheme 2 ). 11 Herein, a synthetic route involving 2-azaallyl anions toward the construction of 3,4-dihydro and fully aromatic β-carbolines with both C1 and C3 aryl substitutions is described. The photophysical properties of the resulting collection of alkaloid-inspired fluorophores were explored and compared using molecular orbital calculations.…”

Fe3O4@GlcA@Cu-MOF: A Magnetic Metal–Organic Framework as a Recoverable Catalyst for the Hydration of Nitriles and Reduction of Isothiocyanates, Isocyanates, and Isocyanides

“…Nitriles are relatively stable functional group that transformed by transition metal catalysis in organic syntheses. − The conversion of nitriles into amides by conventional acid/base reagents or catalysts (Scheme A,B) is a useful transformations in organic chemistry. It usually requires harsh reaction conditions and remains impractical for many purposes due to issues of low yield and selectivity, since classical methods are frequently unable to control the overhydrolysis of the primary amide product.…”