Unreactive C-N Bond Activation of Anilines via Photoinduced Aerobic Borylation

Transition-metal-free photochemical reductive denitration of nitroarenes

We have developed a simple and mild photochemical process for the reductive denitration of nitroarenes under transition-metal-free conditions. This method is compatible with a broad range of functional groups, providing a practical and efficient approach for converting nitroarenes into denitrated arenes. The utility of this protocol is demonstrated through the prompt synthesis of dibenzoxepane.

Quasi-Homogeneous Photocatalysis in Ultrastiff Microporous Polymer Aerogels

The development of efficient and low-cost catalysts is essential for photocatalysis; however, the intrinsically low photocatalytic efficiency as well as the difficulty in using and recycling photocatalysts in powder morphology greatly limit their practical performance. Herein, we describe quasi-homogeneous photocatalysis to overcome these two limitations by constructing ultrastiff, hierarchically porous, and photoactive aerogels of conjugated microporous polymers (CMPs). The CMP aerogels exhibit low density but high stiffness beyond 105 m2 s-2, outperforming most low-density materials. Extraordinary stiffness ensures their use as robust scaffolds for scaled photocatalysis and recycling without damage at the macroscopic level. A challenging but desirable reaction for direct deaminative borylation is demonstrated using CMP aerogel-based quasi-homogeneous photocatalysis with gram-scale productivity and record-high efficiency under ambient conditions. Combined terahertz and transient absorption spectroscopic studies unveil the generation of high-mobility free carriers and long-lived excitonic species in the CMP aerogels, underlying the observed superior catalytic performance.

Photocatalyst- and Transition Metal-Free Light-Induced Borylation Reactions

The increasing global warming concerns have propelled a surge in the demand for sustainable energy sources within the domain of synthetic organic chemistry. A particularly prominent area of research has been the development of mild synthetic strategies for generating heterocyclic compounds. Heterocyclic compounds containing boron have notably risen to prominence as pivotal reagents in a myriad of organic transformations, showcasing their wide-ranging applicability. This comprehensive review is aimed at collecting the literature pertaining to borylation reactions induced by light, specifically focusing on photocatalyst-free and transition metal-free methodologies. The central emphasis is on delving into selective mechanistic investigations. The amalgamation and analysis of these research insights elucidate the substantial potential inherent in eco-friendly approaches for synthesizing heterocyclic compounds, thus propelling the landscape of sustainable organic chemistry.

Transition Metal-Free Aromatic C-H, C-N, C-S and C-O Borylation

Aromatic organoboron compounds are highly valuable building blocks in organic chemistry. They were mainly synthesized through aromatic C-H and C-Het borylation, in which transition metal-catalysis dominate. In the past decade, with increasing attention to sustainable chemistry, numerous transition metal-free C-H and C-Het borylation transformations have been developed and emerged as efficient methods towards the synthesis of aromatic organoboron compounds. This account mainly focuses on recent advances in transition metal-free aromatic C-H, C-N, C-S, and C-O borylation transformations and provides insights to where further developments are required.

Photoinduced Divergent Deaminative Borylation and Hydrodeamination of Primary Aromatic Amines

We have developed the divergent deaminative borylation and hydrodeamination of primary aromatic amines using bis(pinacolato)diboron. These transformations can be switched by the reaction conditions. Mechanistic and computational studies have suggested that the cleavage of the C-N bond and the formation of C-B bond are unlikely to involve free aryl radical intermediates. However, hydrodeamination is shown to proceed via hydrogen atom transfer between the corresponding aryl radical and an ethereal solvent.