Alkyl halides are a class of important organic feedstock with wide availability in organic synthesis. Minisci C-H alkylation is a classical radical-type reaction to effectively introduce alkyl groups into heteroaromatics. The attempt to utilize alkyl halides as radical precursors in Minisci reaction is challenging, which has attracted widespread attention. Although halogen-atom transfer (XAT) provides an available strategy to convert alkyl halides into corresponding carbon radicals, the usage of equivalent XAT reagents and excess oxidants is usually inevitable in Minisci reactions. Herein, we present a traceless aminoalkyl radical-induced XAT process for Minisci reaction, especially without the participation of excess XAT reagents and oxidants. This protocol is compatible with a wide array of sensitive functional groups. Mechanistic experiments indicated the formation of comparable aminoalkyl radicals occurred through SET reduction of protonated heteroaromatics, a process differing from the conventional oxidation method used to generate α-aminoalkyl radicals. Notably, this photocatalytic mode for such aminoalkyl radical generation and XAT-induced Minisci reaction contributes to a redox neutral strategy for coupling of two electrophilic molecules.

The recycling of polyolefin plastics is often hindered by high energy consumption and low economic efficiency. In particular, the recycling of poly(vinyl chloride) (PVC) is especially challenging. Here, we present an innovative protocol to recycle discarded PVC into a photothermal catalyst for the depolymerization of polyolefins under sunlight. By dechlorinating the PVC, we harness its unique ability to converts sunlight into the energy required to break C-C bonds in polyolefins. This protocol allows for the transformation of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) into waxes enriched with terminal olefins, which can be further utilized for the synthesis of surfactant. Furthermore, this protocol enables the conversion of polystyrene, poly(methyl methacrylate), poly(α-methyl styrene), styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene (ABS) into their respective monomers. This broad applicability makes our protocol suitable for the recycling of a wide range of real-life plastic products and their mixtures under ambient environment. Notably, with the aid of just 0.1 wt% catalyst, a successful depolymerization of kilogram-scale PS waste, such as plastic cups, using solar energy has been achieved. Additionally, the catalysts derived from PVC can be reused, thereby enhancing the sustainability and cost-effectiveness of the depolymerization of polyolefins. Our study presents a promising solution to the recycling of PVC and polyolefin plastics, leveraging solar energy to create a sustainable and efficient recycling process.

Naturally occurring dimeric products have attracted considerable attention from both chemists and biologists. The construction of pseudo-dimers often requires elaborate synthetic effort with low efficiency. Dearomatization reactions represent an ideal method to transform planar aromatics into three-dimensional skeletons, which has attracted increasing interest in medicinal chemistry and total synthesis. Herein, we present a self-fusion of N-heteroarenes via an energy transfer-induced dearomatization under photocatalysis. With aromatic compounds as coupling partners, this reaction enables the straightforward construction of pseudo-dimers of N-heteroarenes. This protocol features a broad substrate scope, atomic economy, and metal-free catalysis. Mechanistic studies revealed the intertwined EnT/SET nature in this process and offered guidelines for synthesizing novel bridged polycycles. In addition, this strategy provides an effective approach for constructing functional polymers with high atomic economy and environmental benefits by metal-free one-pot polymerization. Furthermore, the synthetic transformations provide a supplement for the synthesis of formal cross products that were previously inaccessible.