Regioselective Synthesis of 3-Substituted Isocoumarin-1-imines via Palladium-Catalyzed Denitrogenative Transannulation of 1,2,3-Benzotriazin-4(3H)-ones and Terminal Alkynes

A palladium-catalyzed denitrogenative transannulation strategy to access various 3-substituted isocoumarin-1-imine frameworks using 1,2,3-benzotriazin-4(3H)-ones and terminal alkynes is described. The reaction is highly regioselective and tolerates a wide range of functional groups. The reaction is believed to proceed via a five-membered palladacycle intermediate extruding environmentally benign molecular nitrogen as a by-product. The utility of this method was showcased through the one-pot synthesis of biologically relevant 3-substituted isocoumarin scaffolds.

Convenient Synthesis of Salicylanilide Sulfonates from 1,2,3-Benzotriazin-4(3H)-ones and Organosulfonic Acids via Denitrogenative Cross-Coupling

An efficient and straightforward approach to synthesize salicylanilide aryl and alkyl sulfonates from 1,2,3-benzotriazin-4(3H)-ones and organosulfonic acids is described. This protocol is operationally simple and scalable, exhibits a broad substrate scope with high functional group tolerance, and affords the desired products in good to high yield. Application of the reaction is also demonstrated by converting the desired product to synthetically useful salicylamides in high yields.

Sustainable Bioengineering of Gold Structured Wide-Area Supported Catalysts for Hand-Recyclable Ultra-Efficient Heterogeneous Catalysis

Metal nanoparticles grafted within inert and porous wide-area supports are emerging as recyclable, sustainable catalysts for modern industry applications. Here, we bioengineered gold nanoparticle-based supported catalysts by utilizing the innate metal binding and reductive potential of eggshell as a sustainable strategy. Variable hand-recyclable wide-area three-dimensional catalysts between ∼80 ± 7 and 0.5 ± 0.1 cm² are generated simply by controlling the size of the support. The catalyst possessed high-temperature stability (300 °C) and compatibility toward polar and nonpolar solvents, electrolytes, acids, and bases facilitating ultra-efficient catalysis of accordingly suspended substrates. Validation was done by large-volume (2.8 liters) dye detoxification, gram-scale hydrogenation of nitroarene, and the synthesis of propargylamine. Moreover, persistent recyclability, monitoring of reaction kinetics, and product intermediates are possible due to physical retrievability and interchangeability of the catalyst. Finally, the bionature of the support permits ∼76.9 ± 8% recovery of noble gold simply by immersing in a royal solution. Our naturally created, low-cost, scalable, hand-recyclable, and resilient supported mega-catalyst dwarfs most challenges for large-scale metal-based heterogeneous catalysis.

Trifluoroacetic Acid-Mediated Denitrogenative ortho-Hydroxylation of 1,2,3-Benzotriazin-4(3H)-ones: A Metal-Free Approach

An efficient trifluoroacetic acid-mediated denitrogenative hydroxylation of 1,2,3-benzotriazin-4(3H)-ones is described. This metal-free approach is compatible with a wide range of 1,2,3-benzotriazin-4(3H)-ones, affording ortho-hydroxylated benzamides in good to high yields with a short reaction time. The reaction is believed to proceed via a benzene diazonium intermediate. The synthetic utility of the reaction was successfully demonstrated by the preparation of an antimicrobial drug, Riparin C, and benzoxazine-2,4(3H)-diones in good yields.

Synthesis of ortho-arylated and alkenylated benzamides by palladium-catalyzed denitrogenative cross-coupling reactions of 1,2,3-benzotriazin-4(3H)-ones with organoboronic acids

An efficient palladium-catalyzed denitrogenative cross-coupling reaction of 1,2,3-benzotriazin-4(3H)-ones with organoboronic acids is described. The reaction affords various ortho-aryl and alkenylated benzamides in good to high yields.

Potassium tert-butoxide mediated aerobic hydroxylation of arylboronic acids: an application towards the synthesis of (E)-phenoxy acrylates

The first example of potassium tert-butoxide mediated aerobic hydroxylation of arylboronic acids affording phenols is described.

A Zn based metal organic framework as a heterogeneous catalyst for C–C bond formation reactions

A Zn-Bp-BTC MOF was synthesized and characterized. The Zn-Bp-BTC MOF was successfully employed as a catalyst for Knoevenagel condensation, a multicomponent reaction and in benzimidazole synthesis.

Nickel-catalyzed highly chemo- and stereoselective borylative cyclization of 1,6-enynes with bis(pinacolato)diboron

A highly chemo- and stereoselective nickel-catalyzed borylative cyclization of 1,6-enynes with bis(pinacolato)diboron.

Alkene-assisted nickel-catalyzed regioselective 1,4-addition of organoboronic acid to dienones: a direct route to all-carbon quaternary centers

A nickel-catalyzed highly regioselective 1,4-addition reaction of boronic acids to dienones to form products with an all-carbon quaternary center is described. The 3-alkenyl group of dienones is the key for the reaction to proceed smoothly. A mechanism involving the coordination of the dienyl group to the nickel center is proposed.

Cobalt-catalyzed regio- and stereoselective intermolecular enyne coupling: an efficient route to 1,3-diene derivatives

The reaction of alkynes with vinyl arenes or vinyl trimethyl silane in the presence of a cobalt(II) complex, Zn and ZnI(2) in CH(2)Cl(2) at rt to 50 degrees C provides 1,3-dienes in good to excellent yields.