Turning Aggregation into a Mode of Activation: An Application in Photoinduced Anti-Markovnikov Hydroarylation

A photoinduced transition metal-free anti-Markovnikov hydroarylation has been established without the need for any external photocatalyst. Here, aggregation-induced emission triggers this photochemical transformation and also serves as an ecofriendly, real-time indicator for monitoring the progress of the reaction. This method eliminates the need for auxiliary photocatalyst or waste-generating analytical reagents, aligning closely with a sustainable chemical process. This methodology follows several key principles of green chemistry by avoiding transition metals, relying exclusively on inexpensive, nontoxic reagents and employing water as a green cosolvent. This process achieves an impressive E-factor and EcoScale, outperforming existing strategies. The reaction can be easily scaled up with favorable efficiency, showcasing its practical applicability. This method also exhibits a broad substrate scope and a high functional group tolerance. Detailed spectroscopic and deuterium-labeling experiments indicate that a radical-polar crossover mechanism is the primary reaction pathway. Furthermore, DFT studies provide valuable insights into the formation of noncovalent adducts and offer a rationale for the major reaction pathway.