An iron catalyzed deoxygenative diborylation of ketones to access a variety of internal gem-diboronates has been developed. A scale-up synthesis of such gem-diboronates is also applicable under this condition. Meanwhile, common organic solvent acetone was used as start material to synthesize corresponding internal gem-diboronate, and further mono- or di-functionalization of such internal gem-diboronate has also been explored to demonstrate the synthetic potential of internal gem-diboronates.

Allylsilanes have emerged as synthetically useful intermediates that can undergo a variety of chemical transformations and have been found versatile applications in C-C bond construction as well as in preparation of complex molecules. Exploration on the stereoselective route to functionalized allylsilanes is of great significance for the development of organic synthetic methodology. An efficient pathway to a series of novel alkoxy-substituted homoiodio-allylsilanes via the Julia olefination of silylmethyl cyclopropyl carbinols was described. Carbinols derived from cyclopropyl aryl ketone were evidenced to be superiorer in controlling the stereoselectivity of the products than the alkyl equivalents.

The synthesis of α,α,α-iodo-difluoromethyl alcohols via the high selective reduction of iododifluoromethyl ketones by NaBH₄ in methanol at 0℃ was reported. The reaction has some advantages, such as mild condition, simple synthetic route, and high yield. A convenient way to synthesize more difluoromethylation agents was provided.

3-Hydroxy-3-heterocyclebutyl amide derivatives were directly synthesized in 56%~85% yields by nucleophilic addition of various carbamoylsilanes to oxetane-3-one or thietane-3-one in toluene under mild and catalyst-free conditions. This method will provide an efficient route for the synthesis of drugs containing four-membered heterocycles which have not additional stereocentres. The procedure can prepare 3-hydroxy-3-heterocyclebutyl tertiary, secondary and primary amides as well as having a stereocentre connecting with nitrogen atom by selecting different carbamoylsilanes. A comparison of the results obtained from reaction of various carbamoylsilanes indicated that the size of group on the amide group was an important factor in the addition reaction, which influenced on both the reaction time and yields. The reaction has the advantages of mild conditions, less by-products, good yield and simple post-treatment, and is a new method for the efficient preparation of 3-hydroxy-3-heterocycle butylamides.

Carbazole and its derivatives are widely used in the field of medicine and photoelectric materials. A kind of stable cyclic hypervalent iodine reagents containing carbazole group was developed, which belong to benziodoxole compounds. In the presence of Cu(I) catalyst, these reagents reacted with aromatic substrates to give N-aryl carbazole derivatives. The reaction conditions are mild and suitable for a variety of electron-rich arenes. And a radical mechanism was proposed.

A phosphine-mediated Staudinger/Aza-Michael addition of azides with trifluoromethyl substituted α,β-unsaturated ketones was developed, giving hydroamination products in medium to good yields (up to 96%). The hydroamination products could be prepared on gram scale and a wide range of substrates are tolerated under the optimized reaction conditions (30 examples). ³¹P NMR experiments indicate that this reaction was initiated by Staudinger reaction of azide with phosphine.

Organosilanes have been widely applied in synthetic chemistry, pharmaceuticals, agrochemicals, and materials due to the special properties. Several synthetic strategies including nucleophilic substitution, hydrosilylation of alkene, and C-H silylation have been developed. In recent years, significant progress has advanced in the cross-coupling of C-Si bond for the synthesis of organosilanes, especially in the break-through of the cross-coupling of C(sp³)-Si bond. It has become one of the hottest issues in synthetic chemistry. The recent progress on the cross-coupling of C-Si bond by using silyl reagents is summarized. The application of silyl reagents in cross-coupling for C-Si bond formation including silyl boranes, organosilyl magnesium, organosilyl zinc, unasymetric disilanes, organosilyl aluminum and organosilyl lithium reagents is mainly discussed.

Due to the uniqueness of fluorine atom and C—F bond, difluoromethylene has special properties. As a bioisostere of an oxygen or a carbonyl group, it plays an important role in medicines, pesticides and materials. Difluoromethyl heteroaryl sulfones, represented by 2-PySO₂CF₂H (Hu reagent), have been developed recently as difluoromethylation reagents, and widely recognized by synthetic chemists for their ease of preparation, good functional group tolerance and universal applicability to a wide range of carbonyl compounds. Through different types of reactions such as nucleophilic substitution, nucleophilic addition, Julia-Kocienski olefination reaction, and radical-mediated difunctionalization, they introduced difluoromethyl, difluoromethylene, gem-difluoroalkene and other fluorine-containing groups into aldehydes, ketones, and heterocyclic compounds. For the first time, the synthesis of fluorine-containing organic compounds involved in various difluoromethyl heteroaryl sulfones in the past decade is reviewed from the perspective of reaction types and their application studies.

An iodine-dimethyl sulfoxide (I₂-DMSO) promoted efficient method is described for the synthesis of thiazolo- [3',2':2,3]pyrido[4,5-d]pyrido[1,2-a]pyrimidin-5-ones (5) via Pictet-Spengler cyclization. The key intermediate, 2-(3-amino- 5-phenylaminothiazolo-2-yl)-4H-pyrido[1,2-a]pyrimidin-4-one (3), was readily prepared from 2-chloromethyl-4H-pyrido- [1,2-a]pyrimidin-4-one (1) and potassium N-phenyl-N'-cyano-imido-thiocarbonate (2) by Thorpe-Ziegler isomerization. The novel synthetic method offers the advantage of mild reaction conditions, operational simplicity and higher yields.

Penta-coordinated phosphoranes (ab₂) with a five-member cycle and three ligands would simultaneously exchange with themselves under base catalysis to form three different penta-oxy phosphoranes with all the combinatorial ligands referred as a₃, b₃, and a₂b. If we consider a₃ and b₃ as parents, the products obtained from exchange, namely a₂b and ab₂, could be regarded as the offspring of the first generation, leading to the diversified chemical structures. Thus, these fascinating reactions could be considered as a promising chemical model for studying the unique chemistry of possible penta-coordinated phosphorus intermediates in the process of RNA self-splicing, hydrolysis and fusion for gene transcription and biological information storage.

Organosilicon compounds play an important role in pharmaceutical chemistry, material science and organic synthesis. Transition-metal-catalyzed direct silylation of C-H bond, as one of the most concise and efficient methods for the synthesis of organosilanes, has developed rapidly in recent years. In this paper, the recent advance in transition-metal-catalyzed silylation of C-H bonds since 2015 is mainly reviewed.

The formal[6+2] cycloaddition reaction of α'-methylene-2-cyclopentenones and 2-alkylidene-1,3-indanediones was developed under the catalysis of tricyclohexyl phosphine, proceeding in a remote γ-regioselective Rauhut-Currier-type reaction followed by a β'-regioselective intramolecular Michael addition process. An array of fused bicyclic frameworks incorperating a spiro-1,3-indanedione motif were produced in fair to good yields of 48%~76% with excellent diastereoseletivity (generally>19:1 dr). This protocol expands the reaction mode of traditional Rauhut-Currier reaction, which might find further application in organic synthesis.

Rauhut-Currier (RC) reaction is an effective atom-economic method to construct C-C bond. However, the application of this reaction is limited by the lack of selectivity. Herein, an efficient intermolecular cross Rauhut-Currier reaction between chalcones and acrylates in the presence of the tributylphosphine catalyst was developed, the reactions were carried out in mild conditions, and performed well with a series of substrates, delivering the desired products with acceptable to good yields.

In this work, a phosphine-catalyzed[4+1] annulation between salicyl imines and maleimides has been successfully developed, which readily produces spiro[benzofuran-2,3'-pyrrolidine] derivatives in 44%~99% yields. The annulation products were obtained as a pair of syn-and anti-isomers with dr 1.6:1~5:1. The syn-and anti-isomers can be readily separated by column chromatography on silica gel. Thus, this reaction constitutes a simple and efficient method for the synthesis of spiro[benzofuran-2,3'-pyrrolidines]. Presumably, the reaction is initiated by in situ generated non-allylic P-ylide from maleimide and PPh₃, and proceeds through a cascade sequence of nucleophilic addition/intramolecular S_N2-like substitution. It accordingly represents a new example of the phosphine-catalyzed[4+1] annulation via in situ generated non-allylic P-ylides.

The chemistry of frustrated Lewis pairs (FLPs) is among the challenging frontiers of synthetic chemistry, which provides a powerful approach for metal-free catalytic hyrogenations and Piers-type hydrosilylations. In recent years, a significant progress has been made in this field. However, the deveopment of asymmetric reactions is still sluggish. The lacks of highly effective and enantioselective chiral FLP catalysts represent the key issue. C₂-symmetric 1,1'-spirobiindane is one privileged framework in chiral ligands and catalysts. On the basis of chiral binaphthyl diene-derived frustrated Lewis pairs (FLPs) developed by our group, in this work, we designed and synthesized a novel class of chiral spiro dienes, which could further react with Piers' borane via the hydroboration reaction to generate chiral boranes in situ. With the combination of chiral borane and tri-tert-butylphosphine as an FLP catalyst, an asymmetric Piers-type hydrosilylation of simple ketones was successfully realized to give the desired secondary alcohols with up to 90% ee.

Alkaline-earth metals continue to receive growing interest, as they are used as low-cost and non-toxic alternatives to transition-metals in various organic transformations. As ionic character and bond lengths increase along the row in the order Mg²⁺2+2+2+, bond energies decrease along the same row, the corresponding metal hydrides are apt to the formation of insoluble metal hydrides[AeH₂]_∞ (Ae=Mg, Ca, Sr, Ba) through Schlenk equilibrium in solution. Recently, a series of alkaline-earth metal hydrides stabilized by suitable ligands were discovered and characterized, and stoichiometric and catalytic reactions with small molecules were studied as well. In this paper, the recent progress in molecular alkaline-earth metal hydrides is reviewed.

A simple, mild, and high yielding procedure for the iodination of alcohols using a combination of NaBH₄ and I₂ is described. The effectiveness of the protocol is achieved with benzylic alcohols and primary alkylic alcohols whereas allylic and secondary alcohols are found to be unreactive.

β-Ketophosphine oxides are extremely important phosphorus-containing compounds and widely utilitied in the field of organic synthesis chemistry. Developing simple, green and efficient protocol to synthesize β-ketophosphine oxides has attracted great attention of chemists in recent years. The recent advances on the synthesis of β-ketophosphine oxides via phosphorus-centered radical addition reaction or hydration reaction are summarized.

1-Phosphafulvenes are unique in their cycloaddition reactions, which act as 2π, 4π, and 6π systems and provide versatile and powerful approaches to various polycyclic systems. The reaction of 1-phosphafulvene with 1,4-benzoquinone and N-phenylmaleimide upon heating provided phosphapolycyclic rings in moderate to good yields. The possible mechanism included an oxidative addition of 1-phosphafulvene with 1,4-benzoquinone and successive Diels-Alder reactions with N-phenylmaleimide. The exocyclic C=C bond of 1-phosphafulvene is cruial to this reaction.

A highly chemo-, regio-, and stereo-selective cobalt-catalyzed dehydrogenative silylation of vinylarenes was described. The imidazoline iminopyridine cobalt complex could promote this reaction effectively and improve the chemoselectivity dramatically. This protocol used earth-abundant transition metal, readily available alkenes and hydrosilanes to construct valuable vinylsilanes. The reaction could be carried out in gramscale and the proposed mechanism was also described.

The phosphine-catalyzed[3+2] annulation of γ-methyl allenoates with 2-arylidene-1H-indene-1,3(2H)-diones is reported. In the reaction, a series of highly functionalized spiro[4.4]dec-6-ene skeletons were obtained in moderate to good yields and high diastereoselectivities. It should be noted that the perfect α-regioselective annulation adducts were obtained with simple PPh₃ catalyst.

Anodic oxidation of aryl iodine compouds is a green and efficient method for the synthesis of hypervalent iodine reagents. This method replaces chemical reagents with electric current, avoiding the use of expensive and handle difficult oxidants such as m-CPBA, H₂O₂, oxone, selectfluor etc. Electrochemically generated hypervalent iodine reagents can not only promote fluorination, oxidative cyclization, but also be successfully applied in the total synthesis of natural products. In addition, recyclable aryl iodine mediator can be used to indirect anodic fluorination and easily separated from products. The organic electrochemical synthesis of hypervalent iodine reagents and their applications in various chemical transformations are reviewed.

Direct synthesis of organophosphorus compounds from white phosphorus (P₄) is of great significance because this process avoids the industry pollution synthetic methods and provides the possibilities for many novel phosphorus-containing compounds. A trinuclear rare-earth metal complex[{(η⁵-C₅Me₅)LuCl}₃(THF)P₆] [Li(THF)₄] from lutetacyclopentadiene mediated P₄ functionalization was isolated and characterized. This novel complex contains a bicyclo[3.1.0]-P₆^4- ligand which is an unreported type. X-ray diffraction analysis shows that the bicyclo[3.1.0]-P₆^4- ligand adopts a boat-like conformation. Three lutetium atoms coordinate to this ligand in η¹, η³, η³ mode, respectively, and a novel[P₆Lu₃] cage has been formed. Density functional theory (DFT) calculations indicate that there are two three-center two-electron bonds.

A dehydrative cross coupling of ketone-stabilized phosphorus ylides with the readily available allylic alcohols followed by an one-pot Wittig reaction is developed. A range of functional 1,4-dienes could be obtained in 52%~95% isolated yields in the presence of 5 mol% Pd(PPh₃) ₄ and 20 mol% B(OH) ₃. The same method can be extended to ester or nitrile-stabi-lized phosphorus ylides, affording the corresponding 1,4-dienes in moderate yields.

An efficient multicomponent one-pot reaction was developed for the synthesis of α-trifluoromethyl homoallylic hydrazides from the reactions of ethyl trifluoropyruvate, hydrazides and allylic bromide with tin powder in the presence of Brønsted and Lewis acid in 1,4-dioxane under reflux. The method avoids the use of toxic stannanes and allows easy operation. The reaction proceeds smoothly under mild reaction conditions to give the corresponding products in good yields.

The phosphaalkenes, as an important part of organophosphorus chemistry, play a very important role in the field of homogeneous catalysis and functional materials due to special properties of P=C unit. However, the difficult access to phosphaalkene compounds and their less stability have severely retarded the progress of the phosphaalkene chemistry. In this paper, the recent advances in phosphaalkenes, introducing the properties, synthetic methods, and applications of phosphaalkenes to provide some reference for related researcher are reviewed.

The selective reduction of carbonyl group with organosilane as reducing agent was studied with methanol as a solvent under the action of 2.5 mol% C₆H₅BF₃K and 2.2 epuiv. (EtO)₃SiH. The target products were obtained in medium to high yield. This method shows good selectivity and provides a new method for carbonyl reduction.

Using the splicing principle of combining the pharmacological group triazene with 1,3,4-thiadiazole, 15 unreported 1,3,4-thiadiazole triazene derivatives were synthesized. The structures of the compounds were determined by nucleated magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR) and high-resolution mass spectrometry (HRMS). By using the typical triazene drug dacarbazine (DTIC) and drug 5-fluorouracil (5-FU) as a reference, the activity detections of human esop-hageal cancer cells (EC109), human gastric cancer cells (MGC803), and human prostate cancer cells (PC-3) were carried out. The results showed that some compounds inhibited human gastric cancer cells (MGC803) more strongly than dacarbazine (DTIC), and the IC50 values of compounds 2-(3-methyanilino)-5-[4-(3,3-dimethyltriazol-1-yl) phenyl]-1,3,4-thiadiazole (8c), 2-(2-methoxyanilino)-5-[4-(3,3-dimethyltriazol-1-yl) phenyl]-1,3,4-thiadiazole (8f), and 2-(3,4-dichloroanilino)-5-[4-(3,3-di-methyltriazol-1-yl) phenyl]-1,3,4-thiadiazole (8l) were lower than those of 5-fluorouracil with 5.3, 6.5 and 6.3 μmol/L, respec-tively. Some compounds inhibited human prostate cancer cells (PC-3) more strongly than dacarbazine (DTIC), and the IC50 value of 8l is lower than that of 5-fluorouracil with 13.5 μmol/L.

Organic molecules containing trifluoromethyl groups often exhibit unique physical and chemical properties, and have found extensive applications. Trifluoroacetic acid and its derivatives have advantages including low cost, ready availability and high stability. Furthermore, CO₂ is the byproduct. Therefore, trifluoroacetic acid and its derivatives are ideal trifluoromethylating reagents, and have great application potentials. The progress of trifluoromethylation reactions using trifluoroacetic acid and its derivatives as CF₃-sources is reviewed, including the reactions of C-X (X=Br and I), C-H, and C=X (X=C, O). The mechanisms are also introduced.

Diaryliodonium salts with fluorines have potential bioactivity. Vicinal trifluoromethanesulfonate substituted diaryliodonium salts were synthesized for the purpose of studying their anti-bacterial properties aganist Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis). Firstly, their chemical structures were characterized by ¹H NMR, ¹³C NMR, ¹⁹F NMR and mass spectra. The minimum inhibitory concentration (MIC) of these compounds was tested by the micro-broth dilution method. The most active 2-((3-fluorophenyl)(((trifluoromethyl)sulfonyl)oxy)-l3-iodanyl)- phenyl trifluoromethanesulfonate (1) containing fluorine group gave the promising results for Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) (MIC values of 16, 4 and 4 μg·mL^-1), which is significantly lower than the commercial antibacterial agent of isothiazolinones. Scanning electron microscope (SEM) analysis sugggested that the compound led to the death of bacteria. Cytotoxicity tests showed that the compound 1 as well as isothiazolinones had a slight effect on the growth of Hela cells in vitro conditions.

A facile and efficient I₂O₅ promoted iodosulfonylation of alkynes for direct synthesis of (E)-β-iodovinyl sulfones is described. This procedure affords various synthetically useful β-iodosulfonyl alkenes in moderate to good yields under peroxide free conditions.

A facile approach for thioetherification of 4-hydroxycoumarins with arylsulfonyl hydrazides promoted by tetrabutylammonium iodide in the presence of hydrochloric acid was developed generating a series of 3-arylthio-4-hydroxycoumarins in 65%~94% yields. Broad scope and easy availability of substrates, simple operation and high yields of products are the advantages of this method.

Trifluoromethylthiolation/oxidation of styrenes with easiy-handling AgSCF₃ used as the trifluoromethylthiolating reagent has been described, which furnished a series of α-trifluoromethylthio acetophenons. A variety of substituted styrene could be bifunctionalized via radical process in a mixed solvent of dimethyl sulfoxide (DMSO) and CHCl₃, with potassium persulfate used as the oxidant under mild conditions. A simple and efficent method for the facile construction of various α-trifluoromethylthio acetophenons is thus demonstrated.

Recently, the preparation of fluorinated compounds through difunctionalization strategies has become a hot research area in fluorine chemistry. In this work, a copper-catalyzed hydroxytrifluoromethylthiolation of arylpropynones for the synthesis of the corresponding trifluoromethylthiolated enols was developed. The copper salt and solvent are crucial to the yields of this reaction. Under optimized reaction conditions, a series of trifluoromethylthiolated enols were obtained in moderate to good yields.

The addition reaction of perfluoroalkanesulfenic acids, in-situ formed from imines, to alkynes and allenes were investigated. A series of perfluoroalkyl alkenyl sulfoxides were synthesized. Markovnikov adducts were obtained in good to excellent yields from the reactions of aryl or alkyl-substituted alkynes with perfluoroalkanesulfenic acids under mild conditions. However, the reaction of terminal alkynes containing an electron-withdrawing group afforded Michael-type adducts in good yields. The addition reaction of electron-rich allenes took place at the double bond with less steric hindrance, while the double bond connecting an electron-withdrawing group was the prior reaction site in the case of electron-deficient allenes.

A simple and versatile metal-free protocol for the synthesis of perfluoroalkyated fluorene derivatives bearing phosphonate group is achieved. The reactions proceeded via one-pot three-component condensation of indenones, fluorinated alkynylphosphonates and malononitrile under mild conditions. This protocol is highly regioselective, operationally facile and applicable to a variety of indenones in good to excellent yields.

A nickel-catalyzed direct difluoromethylation of (hetero)aryl bromides with bromodifluoromethane (BrCF₂H) is described. This reaction features high efficiency, broad substrate scope and high functional group tolerance, providing a cost-efficient and straightforward route for applications in medicinal chemistry. Preliminary mechanistic studies reveal that a nickel-based, reductive cross-coupling catalytic cycle is involved in the reaction.

Two electrophilic pentafluoroethylating reagents of pentafluoroethyl(p-methylphenyl)sulfonium bis(carbometh- oxy)methylide (4a) and pentafluoroethyl(4-nitrophenyl)sulfonium bis(carbomethoxy)methylide (4b), and their reactions under mild conditions with β-ketoesters, aryl iodides and heteroaromatics are described.

An efficient method for carbon-carbon bond formation via desulfurative coupling of pyrimidine thioethers/4-phenylquinoline thioethers with alkynes or arylboronic acids is described. The reaction was promoted by a cheap and stable copper salt[copper(I) acetate] and catalyzed by palladium with good yields and wild substrate scope.