Light alkanes are natural organic carbon sources and widely distributed in nature. Transforming them into value-added fine chemicals affords attractively economic and ecological benefits as well as enormous chemical challenges. Herein, we report a practical iron-catalysed photoredox system for C(sp3)–H transformation of ethane, propane, and other light alkanes to C–N and C–C bonds under ambient temperature. The present method with abundant and inexpensive iron salts as photocatalysts exhibits high catalytic efficiency (turnover number up to 8000), mild conditions, and the convenience of being purified and scaled up without chromatography. A photo-induced ligand-to-metal charge transfer between Fe(III) and Cl− generates a highly active chlorine radical that sequentially acts as hydrogen atom transfer catalyst. Therefore, the sustainable, convenient, and environmentally friendly system will find wide applications in high-value-added transformation of natural alkanes with novel inspiration not only for organic synthesis, but also for designing catalytically active organic/inorganic materials.
Here we show a practical iron-catalysed photoredox approach for C(sp3)–H alkynylation of methane, ethane, and other light alkanes without pre-functionalisation processes, producing valuable internal alkynes. The protocol has many advantages, including a concise and efficient system, good selectivity, mild conditions, wide application of the synthesised products, and low cost.
A visible light-induced metal-free C(sp3)–H phenanthridinylation of simple alkanes with isonitrile is developed with H2O2 as a terminal sustainable oxidant.
8 July 2022 in Angewandte Chemie International Edition
Nitroaromatics, as an important member and source of nitrogen-containing aromatics, is bringing enormous economic benefits in fields of pharmaceuticals, dyes, pesticides, functional materials, fertilizers, and explosives. Nonetheless, the notoriously polluting nitration industry, which suffers from excessive discharge of fumes and waste acids, poor functional group tolerance, and tremendous purification difficulty, renders mild, efficient, and environmentally friendly nitration a formidable challenge. Herein, we develop a visible-light-driven biocompatible arene C-H nitration strategy with good efficiency and regioselectivity, marvelous substrate applicability and functional group tolerance, and wide application in scale-up synthesis, total synthesis, and late-stage functionalization. A nitryl radical delivered through unusual β-homolysis of a photoexcited ferric-nitrate complex is proposed to be the key nitrification reagent in this system.