Synthesis of complex molecules via multicomponent reactions (MCRs) in a one-pot reaction manner has emerged as an important means to realize the value-added conversion of cheap and easily available renewable bio-based platform molecules. The diversity and multi-functionality of these biomass-derived molecules provide a fascinating platform for establishing MCRs, and in many cases, the developed MCRs would not be attained from less functionalized substrates. This review introduces some typical examples for the conversion of biomass-derived platform compounds to high value-added products through MCRs. It mainly summarizes the MCRs developed by using polyols, dicarboxylic acids, levulinic acid and furfural derivatives as one of the starting substrates. At the end of this review, a perspective of this direction is also given.

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.

A 1,4-diazabicyclo[2.2.2]octane (DABCO)-catalyzed[4+2] annulation reaction between 2-alkylidenebenzothio phene-3(2H)-ones and allenoate has been developed. The substrate scope includes both electron-withdrawing and electron-donating groups on the benzothiophene moiety. This method can be carried out under mild conditions and gives a wide range of highly functionalized benzothiophene-fused γ-pyran derivatives in good yields with moderate selectivity.

Alkenylphosphoryl compounds could quickly replace two phosphine ligands in Pd(PEt₃)₄ at room temperature to produce the corresponding palladium complexes 3a~3e in high yields. Similar nickel and platinium complexes 3f and 3g were also synthesized by the reaction. Complex 3e could react with HOAc to release alkenylphosphoryl compounds gradually. By further addition of 2 equiv. of PEt₃, the reaction could take place completely, generating a phosphoniun 4 as a precipitation. Being similar to Pd(PEt₃)₄, 3d could also undergo hydropalladation with the combination of phenylacetylene and (EtO)₂P(O)H, forming the expected vinyl-Pd-phosphoryl complex, but with a slower reaction rate. The result indicated that alkenylphosphoryl compounds generated from the palladium-catalyzed hydrophosphorylation of alkynes with H-phosphonates might play a negative role in the hydropalladation step of the catalytic cycle. Complexes 3a~3g and phosphonium 4 were charaterized by NMR analysis. The structures of 3a and 4 were also confirmed by X-ray technology.

In order to discover more potent antifungal, a series of 2-aryl-3,4-dihydroisoquinolin-2-iums were reasonable designed and productive synthesized by introducing benzoic acid and phenol pharmacophores into the 2-position of isoquinoline. Their structures were identified by NMR and HRMS. The preliminary in vitro antifungal results showed that most of the title compounds exhibited moderate to significant inhibitory activities against various phytopathogenic fungi at 50 mg·mL^-1, and were equal to controls (chlorothalonil, carbendazim). The concentration of 50% inhibition rate (EC₅₀) of 2-(3-ethoxycarbonyl-phenyl)-3,4-dihydroisoquinolin-2-ium (4j) against R. solani was 3.8495 mg·mL^-1, which was significantly superior to chlorothalonil (4.6328 mg·mL^-1). All the EC₅₀ values of 5 compounds (7.4583~15.4495 mg·mL^-1) against R. cerealis were better than chlorothalonil (16.0137 mg·mL^-1), and 2-(4-methoxycarbonylphenyl)-3,4-dihydroisoquinolin-2-ium (4f) is the best one. The present results provide valuable information for development of plant-based antifungal agents.

The asymmetric transfer hydrogenation represents one important class of reactions for the synthesis of optically active compounds. A chiral ammonia borane was generated in situ from an H₂ release reaction between chiral phosphoric acid and ammonia borane, which could be regenerated by the assistance of water after the hydrogen transfer process and made this reaction catalytic. With this chiral ammonia borane, asymmetric transfer hydrogenations of β-enamine cyanides were realized to afford the desired products in 48%~98% yields with 61%~95% ee.

Pyruvate dehydrogenase multienzyme complex (PDHc) is a key enzyme linking glycolysis and the tricarboxylic acid cycle. Currently, there is no fungicide targeting pyruvate decarboxylase (PDHc-E1), the purpose of this study was to obtain compounds with bactericidal activity by designing inhibitors against PDHc-E1. On the basis of lead compound L, fourteen novel aminopyrimidine derivatives I were designed and synthesized by the condensation reaction of hydrazine and aldehydes as potential PDHc-E1 inhibitors. The most effective 5-((2-(4-bromophenyl)hydrazono)methyl)-2-methylpyridin-4-amine (I-6) with good E. coli PDHc-E1 enzyme inhibitory activity (IC₅₀=26.45 μmol/L) exhibited most powerful inhibitory potency against Cercospora arachidicola Hori (EC₅₀ 14.11 μg/mL) and Physalospora piricola Nose (EC₅₀ 0.64 μg/mL). Therefore it could obtain the compound with antifungal activity against microorganism PDHc-E1 enzyme by modifying the bridged linkage in lead structure 2-methyl-4-amino-pyrimidine derivatives L.

A mild and efficient ⁿBu₄NBr-mediated oxidative cycloaromatization to prepare β-carbolines from readily available tryptophans and N-methylaniline is described. The present metal free protocol is complementary to the existing methods for the synthesis of aromatic β-carbolines.

The development of efficient methods for the preparation of unnatural amino acids has long been an important goal since their widely application in synthetic and medicinal chemistry. The asymmetric α-functionalization of nucleophilic metalated azomethine ylides, which could be in situ-generated from readily-available aldimine esters, has been recogonized as a powerful strategy to synthesize unnatural amino acids. Over the past 20 years, tranistion metal-catalyzed asymmetric construction of unnatural amino acids using azomethine ylides have been extensively studied. In this review, the progress on metallated azomethine ylides invovled aymmetric transformation for the synthesis of unnatural amino acids is summarized according to eletrophilic reagents.

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.

A novel palladium(0)-catalyzed dearomative spirocyclization reaction of bromophenols has been developed for building a series of spirocyclic architectures containing a quaternary carbon center via[2+2+1] strategy. This method employs inexpensive bromophenols and easily accessible alkynes. It exhibits a broad substrate scope in good yields. Notably, this transformation can be realized with high regioselectivity (>19:1 rr) when using unsymmetrical alkynes, which greatly expands the research scope of phenol dearomatization.

A chiral bifunctional squaramide catalyzed enantioselective formal[3+3] annulation of 4-hydroxy-2H-pyrano[2',3':4,5]pyrano[2,3-c]pyrazole-2,5(7H)-diones and (E)-2-nitroallyl acetates has been developed, which provides an efficient approach to stereocontrolled construction of fused polycyclic 3,4-dihydropyrano[4,3-b]pyran-5(2H)-one scaffold. Under the catalysis of a bifunctional squaramide derived from (1R,2R)-1,2-diphenylethane-1,2-diamine, a wide range of novel fused polycyclic 3,4-dihydropyrano[4,3-b]pyran-5(2H)-one derivatives with two adjacent stereogenic centers are obtained in acceptable yields with high anti-selectivity and moderate to excellent enantioselectivity. Representative transformation of the annulation product to other synthetic valuable compound is achieved without any loss of stereochemical integrity.

A novel method of copper-catalyzed cyclization of 1-aryl-1-cycloalcohols and 1,3-dicarbonyl compounds has been developed, affording various cycloalkane-fused dihydrofurans in moderate to excellent yields. This transformation proceeds under mild conditions and with a good tolerance of functional groups. The mechanistic investigation revealed that the reaction involved radical intermediates.

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.

Eight membered cyclic ether compounds are common structural motifs in natural products and bioactive molecules. The efficient synthesis of eight membered ethers has attracted wide attention for organic chemists. Compared with five-to seven-membered cyclic ethers, the synthesis of eight membered cyclic ethers is more challenging. In this paper, the synthetic methods for eight membered cyclic ethers by transition metal catalysis, ring expansion, retro-Claisen rearrangement, ring-closing metathesis, intramolecular amide enol alkylation and organic catalyzed tandem cyclization are reviewed.

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.

Treatment of PhSbCl₂ with 2 equiv. of (2,6-Cl₂C₆H₃)(2-LiC₆H₄)NLi, which was generated in situ by the interaction of (2,6-Cl₂C₆H₃)(2-BrC₆H₄)NH with 2 equiv. of BuⁿLi, followed by quenching with water, afforded the diamine-stibine compound ((o-(N-(2,6-Cl₂C₆H₃)NH)C₆H₄)₂SbPh (denoted as H₂(^dcpN₂Sb)). H₂(^dcpN₂Sb) undergoes amine-elimination reaction with[Fe(N(SiMe₃)₂)₂]₂ (0.5 euiqv.) to afford an iron(Ⅱ) complex[(κ³-N,N,Sb-^dcpN₂Sb)Fe(THF)] (1) bearing an unique tridentate bisamido-stibine ligand. Solution magnetic susceptibility measurements (μ_eff=4.7(2) μ_B in C₆D₆) reveal a high spin (S=2) electronic structure for 1. Complex 1 represents the first high-spin iron(Ⅱ) complex with organic stibine ligation, and features a long Fe-Sb bond distance of 0.2792(1) nm. Density functional theory (DFT) calculations indicate weak σ interaction betwen the high-spin iron(Ⅱ) center and the antimony atom due to ineffective orbital overlap. Complex 1 can react with organic azides RN₃ to furnish the high-spin (S=2) iron(Ⅱ) complexes that bear tridentate bisamido-stibonium imine ligands[(κ³-N,N,N-^dcpN₂SbN^R)Fe(py)] (R=dcp (2,6-Cl₂C₆H₃), 2; R=Dipp (2,6-ⁱPr₂C₆H₃), 3). These compexes are among the rare metal complexes with stibonium imine ligation. The average Sb-N distance of 0.194 nm in the imine moieties is found comparable to those of the Sb-N bonds in the reported stibonium imine compounds Mes₃SbNCOCl₃ (0.199 nm) and 2-MeC₆H₄)₃SbNSO₂CF₃ (0.196 nm). The reactions of 1 with diazo compounds (R¹R²)CN₂ afford the high-spin iron(Ⅱ) complexes featuring tridentate bisamido-stibonium ylide ligands[(κ³-N,N,C-^dcpN₂SbC^R1,R2)Fe(PMe₃)] (R¹=H, R²=CO₂Bu^t, 4; R¹=Ph, R²=CO₂Et, 5). The average Sb-C distance of 0.206 nm in the ylide moieties is found comparable to those of the Sb-C bonds in the reported stibonium ylide compounds (around 0.20 nm). H₂(^dcpN₂Sb) and 1~5 have been characterized by elemental analysis, ¹H NMR, solution magnetic susceptibility measurements and single-crystal X-ray diffraction studies.

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.

Scientists have found more and more sulfur compounds in food with the development of science and technology, high-precision analytical methods and equipment. In 2015, Flavor and Extract Manufactures Association of the United State published 2816 safe flavors, and there are more than 388 sulfur-containing compounds, accounting for more than 13%. The main smell of sulfur-containing flavors is food, especially the non-staple food and dishes. It is mainly used as food flavor, flower flavor and fruity flavor. Due to the increase of sulfur-containing perfume and flavors demand, its production scale is increasing, the research on synthesis methods is also deepening, and the green and efficient construction methods are also constantly reported. In this review, the recent progress in the construction of sulfide, thiol, thioester and polysulfide perfume & flavors is summarized.

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.

An efficient and one-pot method for the preparation of 2-((2-aminobenzoyl)amino)benzoic acid derivatives has been reported. Twenty 2-((2-aminobenzoyl)amino)benzoic acid derivatives were prepared with 84%~99% yields and nine compounds are new compounds. The effects of electron effect and steric hindrance on the reaction were discussed. It provides an operationally simple, environmentally friendly, high yield and good substrate universality method for the synthesis of 2-(2-aminobenzamide)benzoic acid derivatives. Furthermore, macrolide 4 and quinazolinone 5 can be synthesized from 2-((2-ami-nobenzoyl)amino)benzoic acid (3a) in one-step over 92% yields.

Transition metal catalyzed codimeriaztion of alkenes is an important carbon-carbon bond forming reaction. This efficient reaction has the properties of easily available of starting materials, atomic economy, and good prospects for industrial application, and has been received in-depth and intensive study during the past decades. In this paper, we have systematically studied the ruthenium catalyzed codimerization of N-acetyl enamides with alkenes and found that the ruthenium hydride complex RuHCl(CO)(PCy₃)₂ is highly efficient catalyst for the codimerization of N-acetyl α-arylethenamines 1 with vinylarenes 4, providing the head-to-tail hetero-codimerized products, poly-substituted N-acetyl enamides 5 with high chemo-and regio-selectivity and up to 99% yield. According to the results and the observed phenomena of the codimerization reaction, we proposed a reaction mechanism that the vinylarenes 4 was firstly inserted into the Ru-H bond of the activated ruthenium hydride intermediate to form an allylic metal-intermediate and then codimerized with N-acetyl α-arylethenamines 1 to generate the hetero-codimerized poly-substituted N-acetyl enamides 5. With this proposed reaction mechanism the reaction results and the observed phenomena can be rational explanation.

In order to find efficient and low toxicity anti-tumor drugs, a series of novel 4-aminoquinazoline derivatives containing benzothiazole were designed and synthesized. And their antiproliferative activities against four human cancer cell lines[human breast cancer cell line (MCF-7), human gastric carcinoma cell line (MGC-803), human prostate cancer cell line (PC-3), human gastric carcinoma cell line (HGC-27)] were evaluated by using methyl thiazolyl tetrazolium (MTT) assay. The results showed that most compounds exhibited good antiproliferative activities against the four human tumor cell lines. Among them, 2-((benzo[d]thiazol-2-ylmethyl)thio)-N-(3-chloro-4-fluorophenyl)-quinazolin-4-amine (13n) showed the best antiproliferative activity against MCF-7, MGC 803, PC-3 and HGC-27 cancer cell lines, with IC₅₀ values of (6.01±0.54), (7.63±0.48), (6.16±0.34), (7.59±0.62) μmol·L^-1, respectively. Its activity was better than the positive control gefitinib. Molecular docking showed that compound 13n could bind well with epidermal growth factor receptor (EGFR). In a nutshell, this work provides clues to discover antitumor agent based on the quinazoline scaffold.

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.

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 series of 1,3,4-thiadiazolo[3,2-a]pyrimidinone mesoionic derivatives were designed and synthesized with triflumezopyrim as the leading compound, and their structures were characterized by ¹H NMR, ¹³C NMR, ¹⁹F NMR and HRMS. The preliminary biological activities indicated that the target compounds showed certain insecticidal activities at 100 μg/mL, of which the lethality rates of 2-((4-chlorobenzyl)thio)-8-((2-chlorothiazol-5-yl)methyl)-5-oxo-6-(3-(trifluoromethyl)phen-yl)-5H-[1,3,4]-thiadiazolo[3,2-a]pyrimidin-8-ium-7-olate (8b) and 2-(((2-chlorothiazol-5-yl)methyl)thio)-8-((2-chlorothiazol-5-yl)methyl)-5-oxo-6-(3-(trifluoromethyl)phenyl)-5H-[1,3,4]thiadiazolo-[3,2-a]pyrimidin-8-ium-7-olate (8d) against white-backed planthopper (WBPH) were 70%. Some compounds showed good antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas oryzae pv. oryzicola (Xoc) and Xanthomonas citri pv. citri (Xcc) at 50 μg/mL, and the inhi-bitory rates of 2-((2-(trifluoromethyl)benzyl)thio)-8-((2-chlorothiazol-5-yl)methyl)-5-oxo-6-(3-(trifluoromethyl)phenyl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-8-ium-7-olate (8h) to Xoo and Xoc were 70.91% and 53.34%, respectively, which were better than thiodiazole copper (47.76% and 23.25%) and bismerthiazol (66.97% and 17.24%). The inhibition rate of 2-((3-(tri-fluoromethyl)benzyl)thio)-8-((2-chlorothiazol-5-yl)methyl)-5-oxo-6-(3-(trifluoromethyl)phenyl)-5H-[1,3,4]thiadiazolo[3,2-a]-pyrimidin-8-ium-7-olate (8e) to Xcc was 68.97%, which was better than thiediazole copper (35.85%) and bismerthiazol (37.53%)

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.