Green Oxidation of Isochromans to Isochromanones with Molecular Oxygen Catalyzed by A Tetranuclear Vanadium Cluster

Abstract

Isochromanone is the core structure of many bioactive compounds. Direct oxidation of isochromans is one of leading methods for the construction of isochromanones, while most established processes remain suffering from the use of environmental unfriendly metal oxidants, harsh reaction conditions, and the difficulty in catalyst recycling and production separation. Herein, we report a convenient, cost-effective, and green method for the synthesis of high-value added isochromanones via isochroman oxidations with O2 by a novel heterogeneous vanadium cluster catalyst (Cat.1) under mild conditions. This reaction protocol demonstrates high catalytic activity with good catalyst recyclability and reusability for a wide scope of substrates.

Cu/Ni Keggin-based viologen complexes with water-assisted 1D proton channels for asymmetric supercapacitors

“…As nanoscale clusters formed by high-valent transition metal ions (V 5+ , Mo 6+ or W 6+ ), [19][20][21] polyoxometalates (POMs) are considered a promising class of pseudo-capacitive electrode materials, because of their rich reversible multi-electron redox behavior. [22][23][24][25] In addition, POMs have a hydrophilic O-rich surface, which is conducive to proton jumping and pore formation via water molecules. These can establish an effective hydrogen bonds network to enhance proton conduction, which provides an effective means for proton transport.…”