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A new photocatalytic ring expansion reaction that transforms γ‐lactams into 2‐pyridones is described. The reaction is radical‐triggered and was inspired by a late‐stage oxidation commonly observed in fungal metabolism. The reaction is particularly powerful because it can be included in a one pot process which converts readily accessible furans directly into 2‐pyridones through sequential photo‐induced reactions (energy transfer and electron transfer). The study also unveiled unprecedented reactivity for the mild and metal‐free photocatalyst eosin, wherein it is used to cleave a C−I bond activated only by an electron donor on the neighbouring carbon. [ABSTRACT FROM AUTHOR]

Lately, heterogeneous semiconductor materials have been explored as an emerging type of efficient photocatalyst for photoredox organic synthesis. Among these semiconductors, lead halide perovskite materials demonstrate unique properties towards excellent charge separation and charge transfer, extremely long charge carrier migration, high efficiency in visible light absorption, and long excited states lifetimes, etc. as proved in ground‐breaking solar cell applications, garnering necessary merits for an efficient catalytic system for photoredox organic reactions. Here, the latest progress in heterogeneous semiconductor materials towards this endeavor is examined, with particular emphasis on lead halide perovskite nanocrystals (NCs) in photocatalytic organic synthesis. [ABSTRACT FROM AUTHOR]

Abstract: A newly designed class of acridinium‐based organophotocatalysts bearing an imide group at the C9‐position is presented. To achieve these unprecedented structures, a synthetic strategy based on a novel straightforward oxidative Ugi‐type reaction at the benzylic position of C9‐unsubstituted acridanes was developed. The introduction of the imide‐unit affords a notable photocatalytic activity enhancement, allowing efficient transformations in different oxidative and reductive visible‐light catalytic reactions. [ABSTRACT FROM AUTHOR]

The photocatalyzed addition of several hydrogen donors (ethers, aldehydes, alkanes, amides) onto vinylpyridines was achieved. This approach provided access to alkylpyridines, which are important building blocks for the preparation of compounds with biological activity. The strategy was very simple and straightforward because it required only a small amount of a cheap decatungstate salt as photocatalyst. As an added advantage, the reaction could be performed under sunlight irradiation as well as under flow conditions. [ABSTRACT FROM AUTHOR]

A fast and efficient visible-light metal-free hydroacylation of dialkyl azodicarboxylates is described. Among a variety of activated ketones, phenyl glyoxylic acid and its ethyl ester were identified as suitable photoorganocatalysts. A range of aliphatic and aromatic aldehydes were employed, thus leading to products in high to excellent yields. [ABSTRACT FROM AUTHOR]