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.

The discovery of new chemoselectivity with readily accessible chemicals is important to expand the reaction space for modern chemistry. For dienes and dienophiles, most people will naturally use them to carry out the classic Diels-Alder reaction to construct six-membered cyclic compounds. Here, we demonstrated a chemoselective coupling of butadiene with dienophiles through a stereoselective 1,3-cyclotelomerization. By utilizing robust Ni/IPr catalysis, valuable bicyclic products were created with high regio- and chemoselectivities under mild conditions. Asymmetric cyclotelomerization enabled by chiral NHC ligand was also performed, generating enantioenriched bicyclic compounds. Mechanistic studies reveal that the reaction might start with oxidative cyclometallation between two molecules of 1,3-diene and Ni(0) species, which then undergoes [3+2]-cycloaddition via an electron transfer process. The products can undergo a variety of intricate transformations, which emphasizes the potential applications of this strategy. It is hoped that the discovery of this protocol will further inspire people to rethink the classic organic reactions.

Organic halides play a crucial role in various fields such as pharmaceuticals, pesticides, and materials. The dihalogenation of alkenes is an important pathway to obtain organic halides. However, traditional methods often rely on highly active halogen sources, which may present environmental concerns. In this study, we have developed an efficient electrochemically driven approach for the bromochlorination of alkenes. Traditionally inert nBu4NBr and C2Cl6 were added as the halogen sources to generate Br cation and Cl anion intermediates through paired electrolysis. These intermediates were subsequently captured by the alkenes, thus facilitating the formation of bromochlorides. This strategy successfully avoids the use of highly active halogen sources. Most importantly, the reaction condition is very simple without any additives or catalysts, providing bromochloride products in high chemo-, regio-, and diastereoselectivities