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A functionalization of benzylic C(sp3)–H bonds was established through a mild metal-free intramolecular lactonization protocol in the presence of DDQ/ tert -butyl nitrite as photocatalysts, allowing practical and low-cost access to a series of phthalide products in moderate to excellent yields. Compared with many existing methodologies, this visible-light-driven process exhibits an excellent substrate scope and fascinating features, including the formation of water as the sole byproduct, an abundant and green energy source, commercially available catalysts, and room-temperature reaction. Finally, detailed mechanistic investigations clearly revealed the role of the photocatalysts and molecular oxygen. [ABSTRACT FROM AUTHOR]

A three-component domino reaction for the synthesis of naphtho[2,3- b ][1,6]naphthyridine derivatives has been established. Such strategy exhibited excellent substrate scope including various enaminones and aldehydes that afforded a series of multifunctionalized naphtho[2,3- b ][1,6]naphthyridine derivatives with 70–86% yields. The advantages of bond-forming efficiency, accessibility of starting materials, and water as sole byproducts provide invaluable access to biological 1,6-naphthyridines. [ABSTRACT FROM AUTHOR]

A visible-light photocatalytic aerobic oxidative lactonization of arene C(sp2)–H bonds proceeds in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tert -butyl nitrite (TBN). Under the optimized conditions, a range of 2-arylbenzoic acids is converted into the corresponding benzocoumarin derivatives in moderate to excellent yields. This method is characterized by its atom economy, mild reaction conditions, the use of a green oxidant and metal-free catalysis. [ABSTRACT FROM AUTHOR]

A visible-light photocatalytic aerobic oxidation of benzylic C(sp³)–H bonds proceeded in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tert-butyl nitrite, and acetic acid. Advantages of this aerobic oxidation method include its relatively mild conditions, the use of visible-light irradiation instead of conventional thermal methods, the use of a low catalyst loading, and the ability to oxidize a range of alkylarenes, including xanthenes, thioxanthenes, and 9,10-dihydroacridines, to the corresponding ketones in excellent yields. [ABSTRACT FROM AUTHOR]