A transition metal-free borylation of quaternary ammonium salts has been reported via a 1,2-boronate migrations using benzyl quaternary ammonium salts as substrates and base (potassium bis(trimethylsilyl)amide, KHMDS) with steric hinderance as hydrogen abstractor, B₂pin₂ as the boron source. In this transformation, benzylic monoboronate esters and benzylic 1,1-diboronate esters can be obtained by different quenching methods. This transformation showed a favorable tolerance for benzylic quaternary ammonium with different functional groups. A gram scale synthesis was performed.

The transition metal-catalyzed hydroboration of alkenes and alkynes is one of the most efficient way for the production of boronate esters. This type of reaction is 100% atom economic, the starting material is readily available, and the products are diverse. It is noticed that most of the known catalytic systems are based on late-transition-metals such as Rh, Ir, Pd, Pt, Co, Fe and Cu. The use of early-transition-metals of zirconium and titanium, on the other hand, is very scarce. In this short review, the development of application in zirconium and titanium mediated hydroboration of alkene and alkyne is summarized, and the research trends of this area are also discussed.

A direct deoxygenative silylation of amides with silylboronate reagents is developed in the presence of SmI₂/Mg, affording a variety of high value-added α-aminosilane compounds in moderate to excellent yields with good functional group compatibility. The key to the success of this strategy lies in the merging of activation of amides induced by electron transfer with 1,2-metalate migration. The addition of Xantphos ligand can improve the reaction efficiency. The reactions are operationally simple and proceed under mild conditions, the raw materials are easily available and the products are highly valuable.

Ligand exchange between boron and silicon centers offers a convinient way for the synthesis of organoboron compounds. While such method is well-established for the preparation of arylboranes, examples of alkyl exchange between boron and silicon centers are very rare. Here, it was demonstrated that an N-heterocyclic carbene stablized hydroborenium ion readily reacts with alkylsilanes at ambient conditions to afford the corresponding alkylborenium complexes. Theoretical calculations suggest that the activation of Si—C(alkyl) bonds involves a σ-bond metathesis pathway.

In recent years, multi-resonance thermally activated delayed fluorescence (MR-TADF) materials have attracted wide attention because of their excellent photophysical properties and electroluminescent performance. By introducing electron-deficient and electron-rich centers (such as boron and nitrogen atoms) in the framework of polycyclic aromatic hydrocarbons (PAHs), the HOMO and LUMO can be separated on different atoms due to the opposite resonance effects, which can reduce the singlet-triplet energy gap (ΔE_ST) to achieve TADF properties. Compared with conventional donor-acceptor type TADF materials, MR-TADF materials have rigid skeletons and show short-range charge transfer characteristics, which are conducive to realizing narrowband luminescence with high color purity and high quantum efficiency, making them ideal luminescent materials and widely used in organic light-emitting diodes (OLEDs). Since the first report of MR-TADF materials based on B,N-heteroarenes in 2016, significant progress has been achieved in the development of new materials. However, a timely summary on this topic is still lacking. In this review, the design strategy and synthetic method of MR-TADF materials based on B,N-heteroarenes are summarized, and the recent advances in the development of new molecular skeletons, the backbone modification strategy to tune the properties, and a novel type of chiral MR-TADF materials are discussed. It is expected that the current review would further promote the development and application of MR-TADF materials in the future.

A new amidinatoborylaminosilylene (L)[(1,5-C₈H₁₄)B(1-Ad)N]Si (3, L=PhC(NtBu)₂, 1-Ad=C₁₀H₁₅) has been synthesized. The reactions using 3 in combination of similar compounds (L)[(1,5-C₈H₁₄)B(2,4,6-Me₃C₆H₂)N]Si (1) and (L)[(1,5-C₈H₁₄)B(2,6-ⁱPr₂C₆H₃)N]Si (2) were investigated toward ketone and diketone substrates. When with Ph₂CO, no reaction occurred for 3. However 1 and 2 reacted by an oxidative [1+2]-cycloaddition to produce the SiCO-cycles (L)[(1,5-C₈H₁₄)B(2,4,6-Me₃C₆H₂)N]SiOC(Ph₂) (4) and (L)[(1,5-C₈H₁₄)B(2,6-ⁱPr₂C₆H₃)N]SiOC(Ph₂) (5), respectively. Reactions of 1~3 with anthrone yielded compounds (L)[(1,5-C₈H₁₄)B(R)N]Si(H)OC(C₁₄H₉) (R=2,4,6-Me₃C₆H₂ (6), 2,6-ⁱPr₂C₆H₃ (7), 1-Ad (8)), where the oxidative [1+2] cycloaddition followed by an H^–-migration from the CH₂ group of the central C₆-ring of anthrone under aromatization was suggested to proceed through. Furthermore, reactions of 1~3 with benzil gave SiC₂O₂-cycles as (L)[(1,5-C₈H₁₄)B(R)N]SiO₂C₂(Ph)₂ (R=2,4,6-Me₃C₆H₂ (9), 2,6-ⁱPr₂C₆H₃ (10), 1-Ad (11)) undergoing oxidative [1+4] cycloaddition. Compounds 3~11 have been characterized by NMR (¹H, ¹³C, ¹¹B, and/or ²⁹Si ) and CHN-elemental analysis, of which 3, 5~6, and 8~10 were further illustrated by X-ray crystallography. The molecule structures of these compounds were descibed and the reaction mechanisms were discussed.

Deuterated mono- and difluoroalkyl groups have attracted increasing attention in medicinal and biological studies. Controllable snipping one or two fluorine atoms from widely accessible trifluoromethyl groups followed by deuteration is an attractive method to access these molecules, whereas this has been hindered by the challenges associated with the chemoselectivity control during the defluoriantion process. Herein, a strategy for chemoselective deuterodefluorination reaction of trifluoro- and difluoroalkylacetamides via spin-center shifts is reported. The reaction starts with the attack of a deuterated 4-dimethylaminopyridine-boryl radical (DMAP-BD₂) to the amide oxygen atom, followed by a spin-center shift process to trigger the C—F bond scission. The resulting α,α-difluorocarbonyl radicals undergo deuterium atom transfer to afford the CF₂D-products in high yields and high levels of D-incorporation. Notably, increasing the amount of DMAP-BD₃ enables the selective cleavage of the two C—F bonds, leading to CFD₂-products in good yields meanwhile maintaining good levels of D-incorporation.

The recent progress of 1,4-azaborines in organic and transition metal catalysis is summarized, which consists of three parts. The first part briefly describes the history of 1,4-azaborines, the second part emphasizes on the application of 1,4-azaborines as an organocatalyst in the aerobic photooxidation of triaryl phosphines, and the last part discribes the use of 1,4-azaborines as the ligand in palladium-catalyzed stereoselective borylation of enynes. The future direction of this field is also proposed.

In order to meet the demand of data storage security in the rapid development of information, a π-conjugated triphenylamine-based difluororboron compound (PyTPABF₂) was designed and successfully synthesized. PyTPABF₂ held positive solvatochromism behavior, intramolecular charge transfer property, aggregation-induced emission behavior and high contrast mechanofluorochromic performance. The as-prepared powders PyTPABF₂ exhibited bright green fluorescence (533 nm), which luminescent color switching to khaki (556 nm) under external mechanical stimulation, meanwhile, the color could recover to original state after fuming. The X-ray diffraction (XRD) measurement demonstrated that this phenomenon originated from the process of phase transformation between crystalline and amorphous. More importantly, PyTPABF₂-based data secu-rity paper could be achieved rewritable storage of information. It was of assistance in the rational design of smart luminescent materials.

An electrochemical room-temperature synthesis of masked organoboronic acids RB(dan) (R=alkyl or aryl) has been developed. At room temperature, 1,8-diaminonaphthalene and boronic acids can smoothly participate in this reaction to provide a wide variety of RB(dan) (R=alkyl or aryl) in an undivided cell. The transformation has broad substrate scope and avoids using high-temperature or transition-metal catalysts, making it more sustainable and renewable.

Organoboron compounds are important building blocks in organic synthesis and have been widely applied in materials and pharmaceutical science. The development of practical and concise borylation reactions to synthesize organoboron compounds has always been one of the core topics of organoboron chemistry. Recently, photochemical and electrochemical borylation reactions have gained rapid development and emerged as important methods towards the synthesis of organoboron compounds. The recent research progress concerning photochemical, electrochemical and photoelectrochemical borylation involving aryl and alkyl compounds from the view of energy resources and substrates is reviewed. Additionally, research trends of this area are also discussed.

Polycyclic aromatic hydrocarbons (PAHs) and their derivatives are widely used in the field of organic optoelectronic materials, and the photophyscial properties of polycyclic aromatic hydrocarbons can be effectively modified by heteroatomic doping. By replacing carbon carbon (CC) units with an isoelectronic and isostructural boron nitrogen (BN) units, the electronic structure and intermolecular interactions of PAHs can be fine-tuned, resulting in new BN-heteroaromatics with unique optoelectronic properties and bioactivity. BN/CC isosterism can not only enrich the famlily of heteroaromatics but also promote their applications in the fields of optoelectronic, catalysis and biomedical applications. In particular, the researchers from China have engaged and promoted the development of boron/nitrogen-doped heteroaromaics, leading to some great results. The recent advance of 1,2-BN heteroaromatics in China from the chemistry perspective is summarized, including the synthetic development of 1,2-BN heteroaromatics, as well as their applications in variety of research fields. In the end, the development prospects of BN-heteroaromatics are pointed out. Through highlighting these advances of boron/nitrogen-doped heteroaromaics in China, it is hoped that more researchers will be interested in the synthesis and application of boron/nitrogen-doped heteroaromaics. It is also hoped that this review would stimulate the conversation and cooperation between the chemists and material scientists in the related fields.

The copper-catalyzed cross-coupling reaction of 1,1-bis[(pinacolato)boryl]methane with α-diazophenylacetate as carbene precursor was reported, leading to the construction of C(sp³)—C(sp³) bond. Reaction optimization experiments showed that Monophos ligand was critical for the success of this reaction. In situ oxidation afforded the corresponding primary alcohols instead of the relatively unstable boronates. The reaction has high efficiency and good functional group compatibility. The two-step transformation represents a formal hydroxymethylation of diazoacetates.

As an ideal chemical hydrogen storage material, efficient dehydrogenation and transfer hydrogenation of ammonia borane has attracted increasing attention. Due to the advantages of cheap and easy availability and biocompatibility of earth-abundant metals, the development of homogeneous catalytic dehydrogenation and related transformation of ammonia borane with earth-abundant metals is a significant research topic in this field. Herein, the development of dehydrogenation and transfer hydrogenation of ammonia borane catalyzed by homogeneous cobalt complexes is reviewed.

Multiresonant thermally activated delayed fluorescence (MR-TADF) materials are a series of hot materials to realize ultra-high definition organic light-emitting diode (OLED) display. 5,9-Bis(1,2,3,4-tetrahydroquinoline)-5,9-dihydro-5,9- diaza-13b-boranaphtho[3,2,1-de]anthracene (THQBN) and 7-(tert-butyl)-5,9-bis(6-(tert-butyl)-4,4-dimethyl-1,2,3,4-tetra- hydroquinoline)-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (Tt-THQBN) were designed and synthesized as organoboron based MR-TADF based on tetrahydroquinoline, whose structures were characterized by nuclear magnetic resonance and mass spectrum. The thermal stabilities, electrochemical properties and photophysical properties of these two molecules were measured. They had the similar deep-blue photoluminescence, narrow full-width at half-maximum and high photoluminescence quantum yield with the classical MR-TADF molecules. OLED devices were fabricated employing THQBN and Tt-THQBN as the guest materials. They all had deep blue emission at 455~458 nm. The CIE-y values of devices 2~4 are less than 0.1, and the full width of half maximum (FWHMs) of all devices were narrow, whitin the range of 34~38 nm. Their maximum brightness can exceed 1000 cd•m^–2 without serious efficiency roll-down. The device lifetime LT₉₀ of device 3 with best performance in these devices can reach 99 h at the initial brightness of 1000 cd•m^–2.

Rare-earth metal complexes-catalyzed dehydropolymerization of amine-borane was achieved. Rare-earth metallo- cene alkyl complexes [(C₅Me₄R)₂LnR', R=Me, H; Ln=Sc, Y; R'=CH₂SiMe₃, CH(SiMe₃)₂] were found to be active catalysts for the dehydropolymerization of methylamine-borane (MAB), generating corresponding boron-nitrogen polymer [(MeNHBH₂)_n, PMAB]. The results showed that the polymerization activity would decrease with the increase of ion radius of the metal center or the decrease of the steric hindrance of the supporting ligands. In the mechanistic study, a β-B-agostic-type scandium amidoborane complex was successfully isolated through the stoichiometric reaction of Sc complex with MAB. Moreover, the control experiment confirmed the existence of scandium hydride species, which may be the catalytic active intermediate.

A method for the preparation of N,O-chelated B,B-diaryl tetracoordinated organoboron complexes is disclosed. Using stable and readily available potassium aryltrifluoroborates (ArBF₃K) as the surrogate of the diarylboron (Ar₂B) moieties and isoquinoline-3-carboxylic acid as the precursor of the N,O-chelating ligand, the isoquinoline-3-carboxylate chelated diarylboron complexes can be obtained in the presence of Mn, p-toluenesulfonyl chloride, and base. This reaction is featured by broad substrate scope and functional group compatibility, thus providing a convenient and efficient pathway towards diarylboron complexes.

A nickel-catalyzed intramolecular dearomative arylation reaction of pyridiniums and quinoliniums is developed. In the presence of zinc powder as a reducing agent, the intramolecular Grignard-type addition of arylbromides to the C=N bonds of pyridiniums and quinoliniums proceeds smoothly to render pyridines and quinolines dearomatization, leading to a range of spirooxindole derivatives bearing dihydropyridine and dihydroquinoline moieties in moderate to good yields.

A convenient approach acess to boronic ester containing N,O-acetal structure has been established through the Fe(OTf)₃-catalyzed addition of N,O-acetal with organic boric acid. A series of N-O-acetal boronic ester compounds have been successfully prepared in 58%~98% yields. Moreover, these compounds retain the property of boronic ester and can be used for coupling reaction.

In nature, boron is composed of a mixture of two stable isotopes, ¹⁰B (19.78%) and ¹¹B (80.22%). The isotopical ¹⁰B-enriched compounds play important roles in many fields, such as the nuclear industry and cancer radiate treatment. Therefore, the syntheses of such kind of compounds is of important significance. These isotopical ¹⁰B-enriched compounds can be prepared from ¹⁰B-enriched boranes, however, the synthetic methods of such boranes are few. Herein, the synthetic methods of ¹⁰B-enriched Na¹⁰BH₄, THF•¹⁰BH₃, DMS•¹⁰BH₃, DMA•¹⁰BH₃, NH₃•¹⁰BH₃, Me₃N•¹⁰BH₃, Ph₃P•¹⁰BH₃, and IPr•¹⁰BH₃ were developed. Firstly, Na¹⁰BH₄ was synthesized with commercially available ¹⁰B(OH)₃ as starting material based on the modified literature methods. Then the reaction of Na¹⁰BH₄ and I₂ provided ¹⁰B₂H₆, which could rapidly react with different Lewis bases to afford corresponding L•¹⁰BH₃. Undoubtedly, these approaches provide convenient ways for the synthesis of ¹⁰B-enriched compounds.

α-Boryl carbonyl compounds have traditionally been considered thermodynamically unstable and prone to undergo 1,3-boron migration. In recent years, with the development and understanding of sp³-hybridized boron or tetra-coordinated boron, methods for synthesizing stable and separable α-boryl carbonyl compounds have been actively developed. These methods include the insertion reaction of borane with diazo esters, sulfur ylides and other carbene precursors, the free-radical borylation reaction of α,β-unsaturated carbonyl compounds, and late-stage structural modification reactions of boron-contain- ing compounds. The recent advances in the synthesis of α-boryl carbonyl compounds are reviewed based on different reaction types, and the existing challenges and future research directions are discussed.

Organoboron compounds are important building blocks to create molecular diversity. Strategies that can transform the readily available hydrocarbons into these compounds by C—H borylation are highly attractive. In this context, significant progress has been made towards iridium-catalyzed C—H borylation. Because substituted arenes typically contain ortho-, meta- and para-C—H bonds, regiocontrol has been a long-standing challenge within this type of chemistry. During the past decade, significant progress has been made in the ortho-selective C—H borylation, while the meta-/para-selectivity is still challenging. This review aims to provide a comprehensive overview of this topic on meta-/para-selective aromatic C—H borylation by iridium catalysis. This topic is categorized into directed and non-directed C—H borylation.

A cobalt-catalyzed remote hydroboration of enamines via a sequence of chain walking and hydroboration in the presence of an earth abundant catalyst and a commercially available ligand is reported, providing a rapid access to borylamines. This protocol exhibites mild reaction conditions, broad substrate scope and good functional group compatibility. In addition, the practicability and the potential synthesis value of this reaction were demonstrated by a gram reaction and a variety of synthetic transformations of the borylamine products.