Chinese Journal of Chemistry最新文献

Comprehensive Summary

Cross-electrophile couplings (XEC), a crucial subset of cross-coupling reactions, center on the formation of robust C—C bonds through the union of two electrophiles. Usually, such reactions have primarily been catalyzed by transition metals. However, with the steady advancements in photochemical and electrochemical technologies, XEC reactions have significantly progressed and broadened their scope, allowing for the utilization of a wider array of tolerable functional groups, thus revealing vast application prospects. This review aims to systematically summarize the current prevalent types of electrophiles and delve into their specific application examples within XEC reactions involving electrophiles with identical functional groups. Specifically, XECs between the same type of halides have received considerable attention, whereas carboxylic acids and alcohols are still in the early stages of investigation. Furthermore, certain other common electrophiles remain unexplored in this context. Moreover, this review underscores the remarkable contributions of photochemistry and electrochemistry in the field of XEC reactions, aiming to provide valuable insights and inspiration for researchers. Also, this review hopes to spark further interest in XEC reactions, thereby fueling the continuous development and advancement of this exciting area of research.

Key Scientists

Since the 1960s, advancements in the XEC reaction have been substantial, driven primarily by the application of transition metal catalysts. In this area, many distinguished scientists have contributed their wisdom and efforts. Particularly noteworthy is that, during the systematic study of XEC reactions with the identical functional groups, in 2016, MacMillan achieved a photocatalytic XEC reaction between aryl bromides and alkyl bromides; in 2020, Weix successfully realized a nickel-catalyzed XEC reaction between aryl chlorides and alkyl chlorides. Concurrently, contributions from researchers such as Mei, Wolf, Sevov, Lin, Shen, Browne, Zhang, and Qiu have expanded the scope of XEC reactions to various halides. By 2022, MacMillan and Baran achieved a significant milestone in the XEC between carboxylic acids, further broadening the scope of research in this area. Also, advancements in the XEC of alcohols have been noted, with researchers including Weix, Lian, Tu, and Stahl conducting pioneering work and successfully executing the XEC of protective groups. It is foreseen that the ongoing research endeavors will primarily concentrate on the expansion of diverse electrophiles.

Vicinal stereogenic centers are ubiquitous structural scaffolds in both natural products and synthetic compounds, yet their enantioselective construction remains a significant challenge in organic synthesis. Organoboron compounds are of paramount importance in synthetic chemistry due to their ability to undergo facile transformations, yielding diverse essential chemical bonds such as carbon-carbon, carbon-oxygen, carbon-nitrogen, and carbon-halogen bonds. Transition-metal-catalyzed asymmetric borylative functionalizations of internal alkenes offer a promising strategy for the enantioselective installation of two adjacent chiral centers across carbon-carbon bonds. By leveraging the versatile transformations of the newly introduced boryl unit, this approach holds great potential for expanding the structural diversity of vicinal stereogenic scaffolds. In this concise review, we aim to highlight recent advancements in transition-metal-catalyzed asymmetric borylative functionalizations of internal alkenes, underscore their utility as a versatile approach for constructing vicinal stereogenic centers, and discuss unsolved challenges and future directions in this field.

Key Scientists

Amidst the pressing environmental challenges posed by the prevalent reliance on fossil fuels, it becomes imperative to seek sustainable alternatives and prioritize energy efficiency. Electrocatalysis, which is renowned for its high efficiency and environmental friendliness, has garnered significant attention. Rare earth elements (REEs), distinguished by their unique electronic and orbital structures, play a crucial role in electrocatalysis. The strategic integration of REEs into catalysts allows for the fine-tuning of atomic structures, which in turn, significantly boosts catalytic performance. Despite substantial advancements in rare earth-based materials for electrocatalysis, a comprehensive overview of the regulatory mechanisms involving REEs is lacking. In this mini-review, we systematically explore the regulatory mechanisms of REEs within electrocatalysts and their pivotal roles in essential electrocatalytic processes such as the CO₂ reduction reaction, oxygen reduction reaction, and hydrogen evolution reaction. We commence with an elucidation of REEs, proceed to delineate their regulatory impacts on electrocatalysts and delve into their applications in key electroreduction reactions. We conclude with discussions on current limitations and prospects for further advancements in this burgeoning field of research.

Key Scientists

Comprehensive Summary

As a class of organic dyes, boron-containing compounds play an important role in organic luminescent materials. They have attracted considerable attention due to their unique photophysical properties. Chiral luminescent systems have a wide range of practical applications in biological imaging, optoelectronic devices, information storage and 3D display. Boron-containing chiral luminescent materials can not only effectively improve the luminescent properties of CPL materials, but also bring unique properties to the system, which enables them to be used as favorable CPL emitting materials for an expanded range of applications. Here, we review the research progress of boron-containing chiral luminescent materials by the detailed discuss according to different chiral skeletons, such as point chirality, 1,1’-binaphthyl, [n]helicenes, [2,2]paracyclophane and pillar[5]arenes. We believe that this review is of significance for the development of boron-containing compounds and CPL materials.

Key Scientists

The studies of circularly polarized luminescence (CPL) based on small organic molecules have advanced significantly. However, boron-containing chiral luminescent materials have gained attention only in recent years. In 2019, Zhao's group prepared a binaphthalene derivative modified with triarylborane, representing the organic small molecule luminescent material to exhibit CPL characteristics responsive to both solvent and fluoride ions. In 2020, the Chen's group used the unique luminescence properties and steric effects of triarylborane and triphenylamine to prepare CPL materials based on the planar chiral pillar[5]arenes. In 2021, Wang's group developed a new class of B,N-embedded double hetero[7]helicenes molecules that exhibit strong chiroptical responses in the UV-visible region. In the same year, He's group used asymmetric reactions to synthesize boron-based point-chirality compounds with high efficiency and enantioselectivity. In 2023, Ravat synthesized 1,4-B,N-embedded helicenes exhibiting narrow-band fluorescence and CPL. During this period, Matthias Wagner et al obtained (BO)₂-doped tetrathia[7]helicene via an efficient four-step synthesis, and Zheng reported the nearly pure green circularly polarized electroluminescent device (CP-OLED). In 2024, Chen's group prepared B,N-embedded hetero-[9]helicenes offering a pathway towards significantly enhanced efficiency in helicene-based CPEL.

We reviewed works on radical borylation reactions since 2020 from two aspects. 1. Borylation from alkyl or aryl radicals: This approach involves the generation of alkyl or aryl radicals from various precursors such as halides and carboxylic acids, followed by their reaction with diboron reagents to form boron esters. 2. Borylation from boron-centered radicals: This approach involves generating boron-centered radicals, which then react with substrates to achieve borylation.

Key Scientists