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Herein is the first example of photocatalytic cross-coupling of alkenes with aldehydes by a single catalyst without an external photosensitizer and any additives. Irradiation of the aromatic aldehyde and cobaloxime catalyst results in the formation of an acyl radical, which undergoes radical addition with alkene or indole and subsequently β-H elimination to afford alkenyl ketone. The reaction features cheap and readily available raw materials, a broad substrate scope, and mild conditions, even for late-stage derivatization of bioactive compounds.

In this work, we describe an enantioselective reduction and sulfenylation of isoflavanone derivatives by an ion pair strategy. The chiral cationic catalyst bisguanidinium ( BG ) is capable of chiral induction in catalytic systems. Silane hydride works as a reductant and helps to form an anionic hypervalent silicate complex and intermediates with substrates to pair with chiral catalyst. A series of umpolung sulfur reagents accomplish electrophilic attack in the presence of a silicate anion. Both chemoselectivity and enantioselectivity are good to excellent to afford a wide scope of 4-oxo-4 H -chromene-3-carbonitrile and S -electrophilic reagents. Further transformations were completed to introduce more applications.

We introduce switchable chemoselectivity strategies based on the hydrazone phosphaketene intermediate to synthesize three classes of 1,2,4-diazaphosphol derivatives. First, the five-membered heterocyclic P and O anion intermediates acted as nucleophilic agents in the selective construction of C-P and C-O bonds. Second, the phosphinidene served as a phosphorus synthon, allowing for the formation of C-P and C-N bonds. Finally, a stepwise mechanism, supported by DFT calculations, was invoked to explain the reaction selectivity.

Herein, we report the first asymmetric total synthesis of iheyamine B from 2,2'-bisindoloazepinone using the stereoselective construction of the trans -vicinal 2-oxopropyl moiety in the azepine scaffold. The asymmetric decarboxylative allylic alkylation provided the α-allylated 2,2'-bisindoloazepinone intermediate. The subsequent conversion of the lactam moiety into another allyl group in a trans -selective manner followed by Wacker oxidation of each allyl unit to the corresponding 2-oxopropyl group completed the total synthesis of iheyamine B.

Herein, we report the nickel-catalyzed denitrogenative cyclization reaction of 1,2,3,4-benzothiatriazine-1,1-dioxides with arynes to generate the polysubstituted biaryl sultams with tolerance of a wide diversity of substituents on every subunit. The mechanistic study indicates that the reaction is initiated by the formation of a diradical species, which reacts with a nickel complex to form a nickelacycle intermediate and carries out the subsequent cyclization through insertion of an aryne.

The total synthesis of (±)-hinckdentine A is described herein. A cyanide-catalyzed imino-Stetter reaction of the aldimine derived from ethyl 2-amino-3,5-dibromocinnamate and 5-bromo-2-nitrobenzaldehyde followed by oxidative rearrangement afforded a 2,2-disubstituted 3-indolinone derivative containing the carbon skeleton and all of the functional groups present in the natural product correctly positioned, including three bromine atoms. Subsequent D-ring formation and seven-membered C-ring construction completed the total synthesis of hinckdentine A.

A visible-light photoredox catalyzed radical cascade cyclization of simple ethers with cyanamides is developed at room temperature. This strategy involves sequential inert C sp3 -H/C sp2 -H functionalizations through intermolecular addition reaction of oxyalkyl radicals to N -cyano groups followed by radical cyclization of iminyl radicals in situ generated with C-2 aryl rings. This method allows for efficient synthesis of tetracyclic benzo[4,5]imidazo[1,2- c ]quinazolines. Importantly, this is the first example of an intermolecular-intramolecular radical cascade cyclization reaction of cyanamides.

A novel procedure for the transition-metal-free tandem cyclization/ N -arylation reaction sequence of an aryne with a 1,2,3,4-benzothiatriazine-1,1-dioxide is reported. This reaction goes through the intramolecular homolytic cyclization to generate an N-H biaryl sultam intermediate, which enables aryne insertion to access diversely functionalized biaryl sultam derivatives with high yields. The mechanism study indicates that homolytic cyclization is executed by a diradical species, initiated from the thermal decomposition of 1,2,3,4-benzothiatriazine-1,1-dioxide to release a nitrogen molecule.

We describe the asymmetric total syntheses of naphthylisoquinoline alkaloids. Atroposelective biaryl coupling reaction between naphthyl pinacol boronate and an aryl iodide, bearing ( S )-2-aminopropyl group at the ortho -position using the existing central chirality as an atroposelectivity-controlling group, provided the desired biaryl product with high atroposelectivity, without the use of an external chiral source. From the resulting biaryl product, several naphthylisoquinoline alkaloids were prepared via the stereoselective formation of the isoquinoline framework with the appropriate oxidation state and stereochemistry.

A general synthetic strategy for antirhine alkaloids was developed in this study. The cyanide-catalyzed imino-Stetter reaction of ethyl 2-aminocinnamate and 4-bromopyridine-2-carboxaldehyde afforded the corresponding indole-3-acetic acid derivative. Subsequent formation of the six-membered C ring followed by trans -selective installation of the two-carbon unit at C-15 provided rapid access to the key intermediate. Stereoselective installation of substituents at C-20 allowed the total syntheses of (±)-antirhine, (±)-18,19-dihydroantirhine, and their 20-epimers, all of the known natural products in the antirhine family.

An intriguing cage-like polyhemiketal, nesteretal A ( 1 ), was isolated from the coral-derived actinomycete Nesterenkonia halobia . Its structure was established by extensive spectroscopic and computational methods. Nesteretal A is a highly oxygenated compound featuring an unprecedented 5/5/5/5 tetracyclic scaffold. A possible biosynthetic pathway of 1 from naturally occurring diacetyl was proposed. Compound 1 showed a weak retinoid X receptor-α (RXRα) transcriptional activation effect.

Herein, we have developed visible-light photoredox-catalyzed decarboxylating carboxylic acids for alkylation of heteroarenes under mild conditions. The transformation occurred smoothly without the requirement of stoichiometric oxidants in the presence of 0.3 equiv of base, which benefited from the release of hydrogen (H 2 ) and carbon dioxide (CO 2 ). Various substrates and functional groups were tolerated. Primary mechanistic studies suggest that an oxidative quenching pathway and a reductive quenching pathway are both possible in the catalytic cycle.

A highly concise strategy for the total synthesis of phenanthroindolizidines was developed. The one-pot iterative Suzuki-Miyaura reaction of aryl boronic acids with ortho-bromoaryl N-methyliminodiacetate (MIDA) boronate followed by a second Suzuki-Miyaura reaction with a suitable pyridyl bromide provided ortho-aza-terphenyls. Subsequent saturation of the triple bond, treatment with mesyl chloride, and reduction of the resulting dihydroindolizidinium ring afforded the hexahydroindolizines. A final vanadium-catalyzed oxidative electrocyclization provided the desired alkaloids in only three column-separation operations.

A new protocol for the synthesis of 2,2'-bisindole-3-acetic acid derivatives from aldimines derived from 2-aminocinnamic acid derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2'-bisindole-3-acetic acid derivative as the common intermediate.

Coprisidins A and B (1 and 2) were isolated from a gut-associated Streptomyces sp. in the dung beetle Copris tripartitus. Using a combination of spectroscopic techniques, the structures of the compounds were determined to be the first examples of natural naphthoquinone-oxindole alkaloids. Coprisidin A was found to inhibit the action of Na + /K + -ATPase, and coprisidin B showed activity for the induction of NAD(P)H:quinone oxidoreductase 1.

The total synthesis of rutaecarpine (1) and luotonin A (2) is described through controlled cyclization of a common aldimine intermediate 5 derived from ethyl-2-aminocinnamate and quinazolinone-2-carbaldehyde. The cyanide-mediated imino-Stetter reaction of aldimine 5 provided the corresponding indole derivative 3, from which the total synthesis of rutaecarpine (1) was completed via the formation of a 6-membered C-ring. On the other hand, microwave-assisted thermal 6π-electrocyclization of the common intermediate 5, followed by the formation of a 5-membered C'-ring, allowed the completion of the total synthesis of luotonin A (2).

An efficient C-H activation method for the ortho alkynylation of aromatic N-methoxyamides with hypervalent iodine-alkyne reagent using a ruthenium catalyst is described. The reaction proceeds under mild reaction conditions with broad substrate scope. A possible catalytic cycle involving a ruthenium carboxylate assisted C-H bond cleavage is proposed from the preliminary mechanistic evidence.

A novel method for the regio- and stereoselective synthesis of substituted 3-coumaranones from salicylaldehydes and allenes using a rhodium(III) catalyst has been developed. This procedure gives access to new 2-vinyl-substituted 3-coumaranone compounds. The method involves a Rh(III)-catalyzed aldehyde C-H activation and annulation reactions. Moreover, this Rh(III)-catalyzed [4 + 1] annulation reaction has been applied to 2-aminobenzaldehydes to afford 2,2-disubstituted 3-indolinones.

A synthetic method for highly substituted pyridinium salts from the multicomponent reaction of vinyl ketones/aldehydes, amines, and alkynes using a rhodium catalyst is demonstrated. The catalytic reaction proceeds via an in situ generated imine-assisted Rh(III)-catalyzed vinylic C-H activation.

A "one-pot" tandem substitution/Krapcho reaction is reported for the facile synthesis of α-fluorinated esters and sulfones, which utilizes the byproduct salt formed in the substitution step as an indispensible reagent to facilitate the Krapcho reaction step. This represents the first sustainable tandem reaction that internally recycles the waste salt formed in the upstream step as the reagent for the downstream step.

A highly chemo- and stereoselective cobalt-catalyzed hydroarylative cyclization of 1,6-enynes with aromatic ketones and esters to synthesize functionalized pyrrolidines and dihydrofurans is described. A mechanism involving cobaltacycle triggered C-H activation of aromatic ketones and esters was proposed.

The C3 meta-position of fluorene is utilized to construct high-triplet energy compounds. Incorporating a spiroacridine structure, two new host materials SAFDPA and SAFCz were facilely obtained. Their thermal and photophysical properties are fully investigated. The best efficiencies of 19.4%/21.5% of blue/white devices are achieved by SAFCz.

Several bidentate dihydroimidazolines were prepared and investigated as catalysts for hydrogen transfer reduction of C═N bond with Hantzsch ester. Highly efficient reactions were observed for quinolines and imines with low catalyst loading of 2 mol %. The presence of halogen bonding was elucidated using NMR studies and isothermal calorimeric titrations. Binding constants of the XB donors were also measured using isothermal calorimeric titrations (ITC).

A nickel-catalyzed highly regioselective 1,4-addition reaction of boronic acids to dienones to form products with an all-carbon quaternary center is described. The 3-alkenyl group of dienones is the key for the reaction to proceed smoothly. A mechanism involving the coordination of the dienyl group to the nickel center is proposed.

An unusual trimerization of aldehydes in the presence of cyanide via metal-free aerobic oxidative esterification under ambient conditions is described. Various aromatic aldehydes provided the corresponding oxidative esterification products in good to excellent yields. Mechanistic studies suggested that this reaction would proceed via a two-step sequence: cyanide-catalyzed benzoin condensation of aldehydes and subsequent aerobic oxidative esterification of aldehydes with the resultant benzoin products. The usefulness of this protocol was further demonstrated by converting the resulting trimeric products into other biologically important compounds.

Two unexpected chiral organometallic triangles rather than squares from newly designed 90° chiral di-Pt(II) acceptors were obtained through coordination-driven self-assembly. Their structures were well characterized by multinuclear NMR ((1)H and (31)P) and variable-temperature NMR experiments, ESI-TOF-MS, and elemental analysis. The PM6 semiempirical molecular simulation was employed for the interpretation of the formation and stability of such chiral triangles.

An efficient and mechanistically interesting method for the synthesis of highly substituted isoquinolines by a Rh(III)-catalyzed hydrazone directed ortho C-H bond activation and annulation without an external oxidant is described. This reaction is accomplished via a C-C and C-N bond formation along with N-N bond cleavage.

The synthesis of highly substituted naphthalenes from allylarenes and alkynes is described. This reaction proceeds via π-coordination of an allylic carbon-carbon double bond to the Pd(II) center and is followed by ortho selective C-H bond activation.

Pentanidium-catalyzed α-hydroxylation of 3-substituted-2-oxindoles using molecular oxygen has been developed with good yields and enantioselectivities. This reaction does not require an additional reductant such as triethyl phosphite, which was typically added to reduce the peroxide intermediate. The reaction was demonstrated to consist of two-steps: an enantioselective formation of hydroperoxide oxindole and a kinetic resolution of the hydroperoxide oxindole via reduction with enolates generated from the oxindoles.

An efficient Ru(II)-catalyzed amidation of 2-arylpyridines with isocyanates via C-H bond activation is described.

An efficient method for the synthesis of substituted isoquinolinium salts from benzaldehydes, amines, and alkynes via ruthenium-catalyzed C-H bond activation and annulation in one pot is described.

A highly regio- and stereoselective nickel-catalyzed three-component coupling of alkynes with enones and alkenyl boronic acids to afford highly substituted 1,3-dienes is described. The reaction can also be extended to cyclization of enynes with coupling to alkenyl boronic acids. A possible reaction mechanism involving a five-membered nickelacycle as a key intermediate is proposed.

An efficient method for the synthesis of substituted 1(2H)-isoquinolone derivatives via nickel-catalyzed annulation of substituted 2-halobenzamides with alkynes is described. This protocol is successfully applied to the total synthesis of oxyavicine with excellent yield.

The first Brønsted acid catalyzed asymmetric Mukaiyama aldol reaction of aldehydes using silyl enol ethers of ketones as nucleophiles has been reported. A variety of aldehydes and silyl enol ethers of ketones afforded the aldol products in excellent yields and good to excellent enantioselectivities. Mechanistic studies revealed that the actual catalyst may be changed from the silylated Brønsted acid to the Brønsted acid itself depending on the reaction temperature.

A convenient and efficient method for the synthesis of various arylketones by nickel-catalyzed addition of arylboronic acids to nitriles is described. A catalytic cycle involving Ni(II) species as the catalytic intermediates is proposed to account for the present catalytic reaction.

A new type of competitive human GST inhibitors has been developed via the bioisostere and structure activity profile strategies; we report their discovery, preparation, inhibitory activity, and synergetic effect in combination with chemotherapy drugs against breast cancer cells.

Echinopines A (1) and B (2), novel sesquiterpenoids with an unprecedented rearranged skeleton named echinopane, were isolated from the roots of Echinops spinosus. The structures were elucidated by extensive spectroscopic analysis. The relative configuration of 1 was assigned by a combination of NOESY correlations and a simulation analysis. A plausible biosynthetic pathway for echinopane was discussed.

A rhodium-catalyzed chelation-assisted C-H activation of alpha,beta-unsaturated ketoximes and the reaction with alkynes to afford highly substituted pyridine derivatives is described.

[reaction: see text] In this paper, we wish to report the intramolecular [2 + 2 + 2] cocyclotrimerization of nitrilediynes catalyzed by the CoI2(dppe)/Zn system at 80 degrees C in CH3CN. Under these reaction conditions, various highly substituted nitrilediynes having steric conjunction at the alpha and beta positions to a nitrile group and a bulkier substitution at the terminal carbon of alkyne undergo [2 + 2 + 2] cocylotrimerization to afford tetra- and pentacyclic pyridine derivatives in good to excellent yields.

A facile palladium-catalyzed carbocyclization reaction of aromatic iodides, bicyclic alkenes (norbornadiene, norbornene and oxabenzonorbornadiene), and benzynes to furnish various annulated 9,10-dihydrophenanthrene derivatives is described. The carbocyclization products from oxabenzonorbornadiene were further converted to polyaromatic hydrocarbons via a Lewis acid mediated deoxyaromatization reaction. [reaction: see text].

A new cobalt-catalyzed coupling of aryl halides with thiophenols and alkanethiols is reported. A variety of aryl sulfides can be prepared in excellent yields under mild reaction conditions using 1-2 mol % of CoI2(dppe) and Zn. This new cobalt-catalyzed coupling represents an interesting addition to previously known methods to synthesize thioethers. [reaction: see text].

[reaction: see text] o-Iodoaryl aldehydes react with bicyclic alkenes in the presence of NiBr(2)(dppe) and Zn powder in acetonitrile at 80 degrees C undergoing annulation to give polycyclic ketone derivatives. Surprisingly, o-iodoaryl alkyl ketones also react with bicyclic alkenes to form polycyclic ketones with structures the same as those from the corresponding o-iodoaryl aldehydes.

[reaction: see text] An efficient ring closure of 2-iodophenoxy-, 2-iodobenzyloxy-, and 2-iodobenzylaminoallenes followed by ring opening of oxabenzonorbornadienes leading to the synthesis of 2-benzofuranyl, 1H-isochromenyl, or 1,2-dihydroisoquinoline methyl-1,2-dihydro-1-naphthalenol derivatives catalyzed by palladium complexes is described.

[reaction: see text] A wide range of substituted isoquinolines were synthesized via a highly efficient nickel-catalyzed annulation of the tert-butyl imines of 2-iodobenzaldehydes and various alkynes; examination of the regiochemistry of isoquinolines synthesized indicates that there are two different alkyne insertion pathways for the catalytic reactions.

[reaction: see text] o-Allylbiaryl derivatives have been prepared in good to excellent yields by the palladium-catalyzed three-component reaction of allyl halides, benzynes, and aryl organometallic reagents.

Benzynes, generated in situ from 2-(trimethylsilyl)aryl triflates and cesium fluoride, undergo allylalkynylation with allylic chlorides and alkynylstannanes in the presence of palladium catalyst to give 1-allyl-2-alkynylbenzenes in good to excellent yields. [reaction: see text]

A highly effective protocol for palladium-catalyzed selective arylation and heteroarylation of indolizines at C-3 has been developed. Mechanistic studies unambiguously support an electrophilic substitution pathway for this transformation.

In the presence of Ni(dppe)Br(2) and Zn powder in acetonitrile at 80 degrees C, oxa-bicyclic olefins undergo cyclization with o-iodobenzoate and with beta-iodo-(Z)-propenoates to give the benzocoumarin derivatives in moderate to good yields. This methodology offers a simple efficient way for the synthesis of structurally complicate coumarins in one pot. [reaction: see text]

[reaction: see text] Treatment of various o-iodobenzaldehydes and o-iodophenyl ketones with alkynes in the presence of Co(dppe)I(2) and Zn powder in acetonitrile at 80 degrees C afforded the corresponding indenols in moderate to excellent yields with exceedingly high regioselectivity. For most unsymmetrical alkynes tested, the carbocyclization gave a single regioisomer.