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We have developed a hemin-catalyzed biomimetic oxidative annulation of 2,3-dihydroxybenzoic acid with an array of cyclic enamines to form isochromanones in good to excellent yields and high regioselectivity. This formal [4+2] cycloaddition protocol showed high efficiency and remarkable functional group tolerance. Mechanistic studies indicate the involvement of a single-electron oxidation pathway. Preliminary biological investigations showed that isochromanones 3ag and 3ca exhibited antineoplastic activities against MCF-7 cell lines with IC 50 values of 25.21 and 29.09 μM, respectively.

Iodine is one of the most effective sources for iodination of aromatic compounds; however, its electrophilicity is insufficient for direct iodination. The selection of appropriate environmentally friendly and cost-effective oxidants in combination with iodine for the iodination of aromatic rings, along with its application in the synthesis of natural products, holds significant importance. A highly efficient method utilizing I(III) as the initiator has been successfully developed for monoiodination of arylaldehydes. The method demonstrates good compatibility with a wide range of (hetero)aromatic aldehydes, resulting in moderate to excellent yields, without the need for any toxic, volatile or explosive reagents. The synthesis of seven natural products, namely aristogins A-F and hernandial, was achieved through this iodination followed by Ullmann-type coupling.

This study describes a catalyst-free α-acyloxylation of ketones and a KBr-mediated α-acyloxylation of cyclic ethers. These conversions are effectively mediated by hypervalent iodine(III) reagents serving dual roles as the oxidant and nucleophilic source. Consequently, esters are produced directly in moderate to excellent yields. The proposed method features good functional group compatibility, a broad substrate scope, and high synthetic efficiency and is remarkably environmentally friendly.

A facile approach toward chromenopyrrolidines was achieved under mild conditions via organophotocatalyzed aerobic decarboxylative [2 + 2 + 1] annulation of chromones with N -arylglycines, in which N -arylglycines perform dual roles (i.e., radical precursor and methylene provider). Mechanistic studies suggested that a Giese-type radical addition and consequent Mannich pathway were likely responsible for the annulation reaction.

The main protease (M pro ) of SARS-CoV-2 is a well-characterized target for antiviral drug discovery. To date, most antiviral drug discovery efforts have focused on the S4-S1' pocket of M pro ; however, it is still unclear whether the S1'-S3' pocket per se can serve as a new site for drug discovery. In this study, the S1'-S3' pocket of M pro was found to differentially recognize viral peptidyl substrates. For instance, S3' in M pro strongly favors Phe or Trp, and S1' favors Ala. The peptidyl inhibitor D-4-77, which possesses an α-bromoacetamide warhead, was discovered to be a promising inhibitor of M pro , with an IC 50 of 0.95 μM and an antiviral EC 50 of 0.49 μM. The M pro /inhibitor co-crystal structure confirmed the binding mode of the inhibitor to the S1'-S3' pocket and revealed a covalent mechanism. In addition, D-4-77 functions as an immune protectant and suppresses SARS-CoV-2 M pro -induced antagonism of the host NF-κB innate immune response. These findings indicate that the S1'-S3' pocket of SARS-CoV-2 M pro is druggable, and that inhibiting SARS-CoV-2 M pro can simultaneously protect human innate immunity and inhibit virion assembly., (© 2023 Wiley-VCH GmbH.)

The daphnezomine A-type subfamily of Daphniphyllum alkaloids structurally features a unique aza-adamantane core skeleton and anticipates efficient strategies for completing their syntheses to thoroughly investigate their biological activities. Herein, divergent total syntheses of (-)-daphnezomines A and B and (+)-dapholdhamine B have been accomplished in 16-20 steps from a known epoxide via rapid construction of a common core intermediate. The present work features a Ti-mediated radical cyclization to establish the azabicyclo[3.3.1]nonane ring system, an intramolecular Heck reaction to install the bridgehead all-carbon quaternary stereocenter, a tandem deprotection/reduction/keto amine-carbinolamine tautomerization to furnish the aza-adamantane backbone, and an NIS-promoted 6-endo-trig aminocyclization to assemble the (+)-dapholdhamine B backbone., (© 2023 Wiley-VCH GmbH.)

During the past decades, rheumatoid arthritis had become a serious problem, torturing millions of patients because of unclear pathogenesis and no ideal therapies. Natural products remain an important source of medicines to treat various major diseases such as rheumatoid arthritis (RA) given their excellent biocompatibility and structural diversity. Herein, we have developed a versatile synthetic method for constructing various skeletons of akuammiline alkaloid analogs based on our previous research on the total synthesis of the related indole alkaloids. We have also evaluated the effect of these analogs on the proliferation of RA fibroblast-like synoviocytes (FLSs) in vitro and analyzed the corresponding structure-activity relationship (SAR). Among these analogs, compounds 9 and 17c have demonstrated a promising inhibitory effect on the proliferation of RA-FLSs, with IC 50 values of 3.22 ± 0.29 μM and 3.21 ± 0.31 μM, respectively. Our findings provide a solid foundation for future pharmacological studies on akuammiline alkaloid derivatives and inspiration for the development of anti-RA small molecule drugs derived from natural products., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Bao, Wei, Tao, Bashir, Zhang, Bao, Chen and Zhai.)

Phospholipids (PLs) are important components of physiological metabolism in animals and plants, and they have been widely used in clinical treatment, cosmetics, and industry. With the development of marine resources, marine PLs rich in polyunsaturated fatty acids have attracted increasing attention. As important marine resources, shrimp heads (SH), codfish roe (CR), and squid gonads (SG) contain a high PL content. The antithrombotic, antistroke, anti-inflammatory, pro-angiogenic, and cardioprotective activities of PLs from SH, CR, and SG were evaluated and compared using the in vivo zebrafish model. The results showed that the PL extracts of SH, CR, and SG had significant biological activities, which lays a theoretical foundation for the development and utilization of PLs in marine byproducts in the future, providing a new choice for the prevention of inflammatory and cardiovascular diseases. PRACTICAL APPLICATIONS: In this experiment, phospholipids in seafood from different sources were extracted, and their biological activities were comprehensively evaluated and compared using the zebrafish model to lay a foundation for the development of cardiovascular drugs, health food, special medicinal food, and other effective components. The utilization of marine byproducts not only makes full use of resources, but it also protects the environment., (© 2022 Wiley Periodicals LLC.)

The first asymmetric total synthesis of (+)-alstonlarsine A has been realized. The prominent features of the current synthesis include the following: (i) a Pd/self-adaptable ligand complex-catalyzed asymmetric allylic alkylation of 2-methyl-2-cyclopentenyl carbonate with 2-indolylsubstituted dimethyl malonate to establish the key stereocenter of C15, (ii) an intramolecular nitrile oxide-alkene [3 + 2] cycloaddition (INOC [3 + 2]) to construct the cyclohepta[ b ]indole backbone with the installment of the requisite stereochemistry of the all-carbon quaternary center of C20, and (iii) a late-stage interrupted Pictet-Spengler reaction (IPSR) to rapidly assemble the core structure of (+)-alstonlarsine A.

Cephanolides A-D are cephalotane-type diterpenoids featuring a novel 6/6/6/5 tetracyclic core embedded with a bridged δ-lactone. The asymmetric and divergent total syntheses of cephanolides A-D have been accomplished, proceeding in 11-14 steps from a known alcohol. The salient features of the present work include (i) a substrate-controlled diastereoselective intermolecular Diels-Alder reaction to form the 6-6 cis -fused rings, (ii) a palladium-catalyzed formal bimolecular [2 + 2 + 2] cycloaddition reaction via a partially intermolecular cascade reaction sequence involving multiple carbometalations to rapidly install the key tetracyclic skeleton, and (iii) lactonization and late-stage oxidative diversification to complete total syntheses of the four benzenoid cephanolides.

There is an incontestable need for improved treatment modality for glioblastoma due to its extraordinary resistance to traditional chemoradiation therapy. Boron neutron capture therapy (BNCT) may play a role in the future. We designed and synthesized a 10 B-boronated derivative of temozolomide, TMZB. BNCT was carried out with a total neutron radiation fluence of 2.4 ± 0.3 × 10 11 n/cm 2 . The effects of TMZB in BNCT were measured with a clonogenic cell survival assay in vitro and PET/CT imaging in vivo. Then, 10 B-boronated phenylalanine (BPA) was tested in parallel with TMZB for comparison. The IC50 of TMZB for the cytotoxicity of clonogenic cells in HS683 was 0.208 mM, which is comparable to the IC50 of temozolomide at 0.213 mM. In BNCT treatment, 0.243 mM TMZB caused 91.2% ± 6.4% of clonogenic cell death, while 0.239 mM BPA eliminated 63.7% ± 6.3% of clonogenic cells. TMZB had a tumor-to-normal brain ratio of 2.9 ± 1.1 and a tumor-to-blood ratio of 3.8 ± 0.2 in a mouse glioblastoma model. BNCT with TMZB in this model caused 58.2% tumor shrinkage at 31 days after neutron irradiation, while the number for BPA was 35.2%. Therefore, by combining the effects of chemotherapy from temozolomide and radiotherapy with heavy charged particles from BNCT, TMZB-based BNCT exhibited promising potential for therapeutic applications in glioblastoma treatment.

1,3,5-Triazinanes, as a kind of versatile building block, are applied in the synthesis of chromeno[2,3- d ]pyrimidin-5-one derivatives via two different reaction modes, which perfectly exhibits the powerful function of 1,3,5-triazinane as a three-atom synthon along with the structure variation of another substrate. The two annulation reactions proceed under mild conditions and bear broad substrate scope and high yield.

Lipids are key factors in nutrition, structural function, metabolic features, and other biological functions. In this study, the lipids from the heads of four species of shrimp ( Fenneropenaeus chinensis (FC), Penaeus japonicus (PJ), Penaeus vannamei (PV), and Procambarus clarkia (PCC)) were compared and characterized based on UPLC-Q-Exactive Orbitrap/MS. We compared the differences in lipid composition of four kinds of shrimp head using multivariate analysis. In addition, a zebrafish model was used to evaluate pro-angiogenic, anti-inflammatory, anti-thrombotic, and cardioprotective activities of the shrimp head lipids. The lipids from the four kinds of shrimp head had different degrees of pro-angiogenic activities, and the activities of PCC and PJ shrimp lipids were more significant than those of the other two species. Four lipid groups displayed strong anti-inflammatory activities. For antithrombotic activity, only PCC (25 μg/mL) and PV (100 μg/mL) groups showed obvious activity. In terms of cardioprotective activity, the four kinds of lipid groups significantly increased the zebrafish heart rhythms. The heart distances were shortened, except for those of the FC (100 μg/mL) and PJ (25 μg/mL) groups. Our comprehensive lipidomics analysis and bioactivity study of lipids from different sources could provide a basis for the better utilization of shrimp.

A microwave-promoted multicomponent reaction of 3-formylchromones, amines, and paraformaldehyde was achieved under catalyst-free and solvent-free conditions, delivering 5 H -chromeno[2,3- d ]pyrimidin-5-one derivatives in good to excellent yields via an unexpected annulation pathway, which further expanded the synthetic application of paraformaldehyde as a C1 building block.

We have developed cobalt-catalyzed, bidentate 2-(1-methylhydrazinyl)pyridine (MHP)-directed C( sp 2 )-H alkylation/annulation of benzoic hydrazides with various alkenes. Notably, diverse cyclopenta[ c ]isoquinolinones and dihydroisoquinolinones were obtained via this functional group-tolerant protocol. The reaction can be performed on a gram scale while maintaining an excellent yield, and the directing group can be removed efficiently under mild conditions. Furthermore, density-functional theory (DFT) calculations provide an incisive understanding of the observed regioselectivities for different olefins.

Palladium-catalyzed C(sp 2 )-H arylation of ortho C-H bonds involving 2-(1-methylhydrazinyl)pyridine (MHP) as the directing group has been investigated. The reaction proceeds smoothly under an air atmosphere to generate biaryl derivatives in an environmentally friendly manner while tolerating a wide range of functional groups. Notably, the directing group present in the product could be easily removed under mild reductive conditions., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

(+)-Mannolide C is a complex hexacyclic C 20 cephalotane-type diterpenoid featuring a highly strained 7/6/6/5 tetracyclic core containing eight consecutive stereocenters and two bridging lactones. The first asymmetric total synthesis of (+)-mannolide C has been accomplished by lipase-mediated resolution, Ru-complex-catalyzed double ring-closing metathesis (RCM) reactions, Ni II -catalyzed diastereoselective Michael addition, and Mn III -catalyzed allylic oxidation as the key transformations., (© 2021 Wiley-VCH GmbH.)

The first asymmetric total synthesis of three picrinine-type akuammiline alkaloids, (-)-picrinine, (-)-scholarisine C, and (+)-5-β-methoxyaspidophylline, has been accomplished. The synthesis features an efficient acid-promoted oxo-bridge ring-opening and further carbonyl O-cyclization to assemble the furoindoline scaffold, an unusual Dauben-Michno oxidation to construct the requisite α,β-unsaturated aldehyde functionality, and a nickel-mediated reductive Heck reaction to forge the [3.3.1]-azabicyclic core.

An efficient annulation reaction of aurone-derived α,β-unsaturated imines and activated terminal alkynes mediated by triethylamine is described, which enables the facile synthesis of 1,4-dihydrobenzofuro[3,2-b]pyridines in high yields. When the nucleophile of triethylamine was replaced with triphenylphosphine, another class of 1,4-dihydrobenzofuro[3,2-b]pyridines tethered with an additional acrylate motif were obtained instead. These two types of 1,4-dihydrobenzofuro[3,2-b]pyridines could be aromatized in the presence of DBU to afford benzofuro[3,2-b]pyridines, which could also be accessed via a one-pot procedure.

A Brønsted acid-catalyzed domino ring-opening cyclization transformation of donor-acceptor (D-A) cyclopropanes and 2-naphthols has been developed. This formal [3+2] cyclization reaction provided novel and efficient access to the naphthalene-fused cyclopentanes in the absence of any transition-metal catalysts or additives. This robust procedure was completed smoothly on a gram-scale to afford the corresponding product with comparable efficiency. Furthermore, the synthetic application of the prepared product has been demonstrated by its transformation into a variety of synthetically useful molecules., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhao, Shen, Sun, Zhai and Zhao.)

The regioselective functionalization reaction of unprotected carbazoles with donor-acceptor (D-A) cyclopropanes has been demonstrated for the first time. With Sc(OTf) 3 as Lewis acid catalyst, the N-H functionalization of carbazoles takes place through a highly selective nitrogen-initiated nucleophilic ring opening reaction. Significantly, by engaging TfOH as Brønsted acid catalyst, a straightforward C-H functionalization at the 3-position of the unprotected carbazole proceeds via Friedel-Crafts-type addition. This strategy facilitates the diversity-oriented synthesis of carbazole-containing heterocycles and expands the novel application of D-A cyclopropanes.

The synthesis of two kinds of five-membered organosulfur heterocycles (i.e., 1,4,2-oxathiazoles and 1,3,4-thiadiazoles) from α-enolic dithioesters with active 1,3-dipoles (nitrile oxides and nitrilimines) generated in situ was achieved under mild reaction conditions. This transformation further expands the synthetic application of α-enolic dithioesters as the sulfur-containing building blocks.

Cross-dehydrogenative coupling reactions provide a method to construct new chemical bonds by direct C-H activation without any pre-functionalization. Compared to functionalization of a C-H bond α- to ether oxygen, α- to carbonyl, or at a benzylic position, functionalization of unactivated hydrocarbons is difficult and often requires high temperatures, a transition-metal catalyst, or a superstoichiometric quantity of volatile, toxic, and explosive tert-butylhydroperoxide. Here, a cross-dehydrogenative C-O coupling reaction of N-hydroxyphthalimide with unactivated alkanes, nitriles, ethers, and thioethers has been realized by using iodobenzene diacetate as the radical initiator. The current protocol enables efficient functionalization of unactivated hydrocarbons and nitriles through inert C(sp 3 )-H bond activation under mild reaction conditions. O-substituted NHPI derivatives are generated in good yields under metal-free conditions., (© 2021. The Author(s).)

The synthesis of 3,4-dihydro-2 H -1,3-thiazines from α-enolic dithioesters and 1,3,5-triazinanes has been achieved via a formal (3 + 3) annulation reaction under thermal conditions, where 1,3,5-triazinanes were utilized as three-atom synthons. This transformation is catalyst-free and additive-free.

Cyclopianes are novel diterpenes featuring a highly strained 6/5/5/5 tetracyclic core embedded with 6-8 consecutive stereocenters. The concise total syntheses of (-)-conidiogenone B, (-)-conidiogenone, and (-)-conidiogenol have been accomplished in 14-17 steps. The present work features a HAT-mediated alkene-nitrile cyclization to access the cis-biquinane, a Nicholas/Pauson-Khand reaction to construct the linear triquinane, and a Danheiser annulation to afford the congested angular triquinane skeleton., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel cyclization reaction of pyridinium 1,4-zwitterionic thiolates and propiolic acid derivatives mediated by triethylamine is described, which allows the facile synthesis of indolizines under mild reaction conditions. The net transformation involves an acetylide-driven formal [5 + 1] annulation reaction followed by a spontaneous ring-contraction/sulfur extrusion process of transient pyridothiazine intermediates.

Two reaction modes of pyridinium 1,4-zwitterionic thiolates with sulfenes generated in situ from alkanesulfonyl chlorides are described with DIPEA as the base. 3 H -1,2-Dithiole 2,2-dioxides could be obtained via a formal [3 + 2] pathway from alkylmethanesulfonyl chlorides, while 1,9a-dihydropyrido[2,1- c ][1,4]thiazines were obtained via a stepwise [(5 + 2) - 1] pathway from phenylmethanesulfonyl chlorides. Moreover, as an application, indolizines could be accessed via a stepwise {[(5 + 2) - 1] - 1} pathway, with 1,9a-dihydropyrido[2,1- c ][1,4]thiazines as the transient intermediates.

The synthesis of pyridothiazines was achieved using pyridinium 1,4-zwitterionic thiolates and α-functionalized bromoalkanes via a formal [5+1] pathway. Further studies demonstrated that the synthesis of indolizines could be accomplished via a stepwise [(5+1)-1] pathway with unstable pyridothiazines as the transient intermediates from the same starting materials. The net transformation involves a sequence of annulation, oxidation and ring-contraction/desulfuration.

A cobalt-catalyzed direct C-H/N-H functionalization of thiophene-2-carbohydrazides with maleimides by utilizing 2-(1-methylhydrazinyl)pyridine (MHP) as an easily removable bidentate directing group has been developed. This formal [4+2] cycloaddition has been achieved for the first time, and it provides an alternative and versatile approach to construct thiophene-fused pyridones using an inexpensive cobalt catalyst. The C-H/N-H activation cascade protocol showed a high efficiency and a broad substrate scope, and the products were obtained in good to excellent yields.

Pyridinium 1,4-zwitterionic thiolates, as a novel kind of sulfur-containing synthon, have been applied to the synthesis of 12a H -benzo[ f ]pyrido[1,2- d ][1,4]thiazepines and benzo[ b ]thiophenes. Benzopyridothiazepines were produced through a 1,5-dipolar cycloaddition reaction from pyridinium 1,4-zwitterionic thiolates with arynes, whereas benzothiophenes as side products were generated via a [3 + 2] cascade cyclization reaction. The [5 + 2] reaction mode of pyridinium 1,4-zwitterionic thiolates is disclosed for the first time.

A novel and practical protocol for the synthesis of fully substituted pyrazoles from pyridinium 1,4-zwitterionic thiolates and hydrazonoyl chlorides in excellent yields under mild conditions is described. The transformation proceeds via an unusual [[3 + 3] - 1] pathway, which involves a formal [3 + 3] cascade cyclization followed by a spontaneous ring-contraction/sulfur extrusion reaction from 4H-1,3,4-thiadiazine intermediates.

We have developed a unique approach for the thermally promoted cycloaddition of cyclohexadienone-tethered allenes to form a versatile cyclobutane-fused oxygen-containing tricyclic framework in an environmentally friendly and atomic economic fashion with high regioselectivity. The reaction encompasses a broad substrate scope and functional group tolerance of cyclohexadienone moieties. Moreover, the cycloaddition was also applicable to the late-stage functionalization of pharmaceutically relevant compounds.

A [3+2] cascade cyclization reaction of pyridinium 1,4-zwitterionic thiolates and activated allenes has been developed, which allows facile access to a library of tetrasubstituted thiophenes with great variety under thermal conditions.

Switchable ring-contractive extrusion reactions of 2,5-dihydro-1,4,5-thiadiazepine S- oxides are described, which allow expedient access to pyridazines under thermal conditions or pyrazoles under Lewis acid-mediated conditions.

A novel [4+3] cascade cyclization reaction of pyridinium 1,4-zwitterionic thiolates with azoalkenes derived from α-halo hydrazones in situ has been developed. This reaction was found to allow expedient access to an array of 2,5-dihydro-1,4,5-thiadiazepines. Libraries of highly functionalized sulfoxide and sulfone analogues of 2,5-dihydro-1,4,5-thiadiazepines were also obtained via selective oxidation with m-CPBA.

In this study, BaCe 0.9 Er 0.1 O 3-α was synthesized by a microemulsion method. Then, a BaCe 0.9 Er 0.1 O 3-α -K 2 SO 4 -BaSO 4 composite electrolyte was obtained by compounding it with a K 2 SO 4 -Li 2 SO 4 solid solution. BaCe 0.9 Er 0.1 O 3-α and BaCe 0.9 Er 0.1 O 3-α -K 2 SO 4 -BaSO 4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectrometry. AC impedance spectroscopy was measured in a nitrogen atmosphere at 400-700 °C. The logσ~log ( p O 2 ) curves and fuel cell performances of BaCe 0.9 Er 0.1 O 3-α and BaCe 0.9 Er 0.1 O 3-α -K 2 SO 4 -BaSO 4 were tested at 700 °C. The maximum output power density of BaCe 0.9 Er 0.1 O 3-α -K 2 SO 4 -BaSO 4 was 115.9 mW·cm -2 at 700 °C, which is ten times higher than that of BaCe 0.9 Er 0.1 O 3-α .

The enantioselective total synthesis of cage-shaped alkaloid (+)-arboridinine is reported. The synthesis takes advantage of the stereoselective double-Mannich reaction to rapidly construct the aza[3.3.1]bicyclic core along with two quaternary stereocenters of the alkaloid. Key steps for the present synthesis include an enantioselective Michael addition establishing the original chiral center at C10 and intramolecular dearomative alkylation forging the cage-shaped ring system found in arboridinine, as well as creating the requisite quaternary carbon center at C3. The bridgehead hydroxyl moiety at C11 was installed through a late-stage cobalt-catalyzed decarboxylative acetoxylation reaction. This strategy enables a 14-step asymmetric total synthesis of (+)-arboridinine from the readily available starting materials with most of the transformations performed on the decagram scale.

We have developed a one-pot synthesis of benzo[b]fluorenones via a cobalt-catalyzed [3+2] annulation of oxabicyclic alkenes followed by a ring-opening/dehydration sequence in good to excellent yields. With the use of 2-(1-methylhydrazinyl)pyridine (MHP), first explored by our group as the bidentate directing group in C-H functionalization of benzoic hydrazides, the new reaction sequence proceeded smoothly and tolerated a wide range of functional groups, featuring facile scalability. Notably, oxygen served as the green oxidant in the reaction system. Careful tuning of the reaction parameters assured the direct synthesis of benzo[b]fluorenones through aromatization of the dihydroepoxybenzofluorenone intermediate.

A highly stereoselective synthesis of a spiro-cineole scaffold that contains four stereogenic centers from readily accessible 2-alkynylbenzaldehydes and styrenes under very mild reaction conditions was reported. This cascade reaction involves a Ag(I)-catalyzed alkyne cycloisomerization and oxa-[4 + 2]-cycloaddition to give an oxonium intermediate which subsequently undergoes a previously unexplored 1,2-alkyl migration to access highly strained spiro-2-oxabicyclo[2.2.2]octanes in high yields with excellent stereoselectivities.

A general and efficient protocol was developed for the synthesis of polysubstituted pyridines from propargyl amines and unsaturated carbonyl compounds through a tandem condensation/alkyne isomerization/6π 3-azatriene electrocyclization sequence. This process was found to be applicable to a wide range of readily available substrates (30 examples, up to 95 % yield) and could be readily performed on a preparative (20 g) scale. By taking advantage of this method for late-stage pyridine incorporation, we successfully completed the collective total synthesis of suveoline, norsuveoline, and macrophylline., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel relay Rh (II)/cobaloxime (III) dual catalysis strategy has been developed for the stereoselective synthesis of indolyl spiroindanones from readily accessible N-sulfonyl-1,2,3-triazoles. This binary-catalyst system enables an aza-vinyl carbene initiated Pictet-Spengler-type cyclization and sequential cobaloxime promoted intramolecular Mannich-type reaction cascade. The easily accessible reagents, high diastereoselectivity, and operational simplicity make this reaction a method of choice for the preparation of functionalized spiroindanones, which are difficult to access by other classic reactions in one step.

Rhodium-iminocarbenes that are derived from N-sulfonyl-1,2,3-triazoles have become an important class of reactive species and useful intermediates in organic synthesis. Over the last several years, many practical and versatile approaches involving rhodium-iminocarbene intermediates to synthetically challenging molecules (scaffolds) have been developed. This Minireview mainly summarizes the recent advance of rhodium-iminocarbene involved reactions in the synthesis of natural products and their related scaffolds by the end of 2017. Several applications in important pharmaceuticals are documented as well., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A copper-catalyzed reaction of ethynyl benzoxazinanones with readily accessible β-ketoesters via a decarboxylative propargylation/hydroamination sequence has been developed. This protocol furnished a diverse range of C3 β-ketoester-functionalized indoles in good to excellent yields.

CF3-containing spiro-epoxyoxindoles were successfully prepared via the Corey-Chaykovsky reaction of N-alkyl isatins with the ylide generated from Ph2S+CH2CF3OTf- with almost exclusive diastereoselectivity. Further derivatizations of these spiro-epoxyoxindoles were explored via a photochemical reaction or Lewis acid-promoted allylation.

A cobalt-catalyzed oxidative coupling of benzoic hydrazides with maleimides by utilizing 2-(1-methylhydrazinyl)pyridine as a bidentate directing group has been developed. This C-H functionalization/spirocyclization cascade protocol shows high efficiency and remarkable functional group tolerance, and the ubiquitous spirosuccinimides were obtained in good to excellent yields with high regioselectivity. This strategy also provides a novel and efficient access to diverse symmetric and unsymmetrical bisspirosuccinimides.

A collective asymmetric total synthesis of lundurines A-C using l-pyroglutamic acid derived from the chiral pool is described. The key steps include a tandem reductive amination/lactamization sequence to introduce the pyrrolidinone ring, a palladium-catalyzed intramolecular direct C-H vinylation of indole to construct the crucial polyhydroazocine ring, and a Lewis acid promoted formal [3 + 2] cycloaddition/N 2 extrusion process to install the polysubstituted cyclopropyl ring.

A novel palladium-catalyzed decarboxylative coupling reaction of vinyl benzoxazinanones with arynes which may feature an intramolecular nucleophilic attack of an amino group at the central carbon of π-allylpalladium intermediate has been developed. The cis-5,5a,6,10b-tetrahydroindeno[2,1-b]indoles were generated in moderate to good yields. One key to the success of the present reaction was to achieve comparable rates for the palladium-catalyzed decarboxylation and aryne formation steps.

(-)-Daphnilongeranin B and (-)-daphenylline are two hexacyclic Daphniphyllum alkaloids, each containing a complex cagelike backbone. Described herein are the first asymmetric total synthesis of (-)-daphnilongeranin B and a bioinspired synthesis of (-)-daphenylline with an unusual E ring embedded in a cagelike framework. The key features include an intermolecular [3+2] cycloaddition, a late-stage aldol cyclization to install the F ring of daphnilongeranin B, and a bioinspired cationic rearrangement leading to the tetrasubstituted benzene ring of daphenylline., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient DABCO-catalyzed three-component formal [3 + 2 + 1] annulation, involving a Morita-Baylis-Hillman carbonate, a 1,3-ketoester, and a primary amine, leading to one-pot synthesis of substituted 4-aryl-1,2,3,4-tetrahydropyridines, has been developed. The densely functionalized products were generally obtained in good to excellent yields under mild conditions. The structures including the relative stereoconfigurations of the representative products were confirmed by X-ray diffraction analysis.