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In this paper, we report a gold(I)‐catalyzed cascade cyclization of N‐ or O‐nucleophile tethered‐vinylidenecyclopropanes (VDCPs), resulting in the synthesis of pyrrole, furan, pyrrolidine, and piperidine skeletons in 30%‐98% yields. Depending on the carbon chain length connecting the nucleophile and VDCPs, two reaction pathways are available, leading to different products. Both α‐amino VDCPs and α‐hydroxyl VDCPs, where nucleophiles and VDCPs are connected by a methylene group, undergo intramolecular nucleophilic addition and aromatization, followed by ring‐opening of the cyclopropane unit to produce substituted pyrroles and furans. By extending the chain length to three or four carbons, it becomes possible to form pyrrolidines and piperidines with a cyclobutene moiety via ring expansion of the cyclopropane unit, accompanied by gold carbene induced vinylogous nucleophilic addition. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A copper‐catalyzed [5+1] cycloaddition reaction of terminal alkynes with diazo esters for the rapid construction of protected naphthalen‐1(2H)‐one derivatives in moderate to good yields has been disclosed along with good functional group compatibility and a broad substrate scope. The mechanistic investigations reveal that this tandem cyclization process proceeds through a Cu(I)‐catalyzed coupling of terminal alkyne with diazoacetate, a 1,5‐H shift process and a thermally induced pericyclic reaction via an allene intermediate. The synthetic utility and the further transformations of the obtained cycloadduct to naphthalenone, naphthol and dihydronaphthol have been also presented in this paper. [ABSTRACT FROM AUTHOR]

A cascade cyclization from Weinreb amide‐tethered methylenecyclopropanes and alkynes has been disclosed in this paper, which extends the umpolung ring opening of methylenecyclopropanes, giving a synthetic approach for the construction of polycyclic cyclopenta[b]naphthalenol framework. In the protocol, four carbon‐carbon bonds and two carbocycles are formed without the use of transition metals, providing a tool for constructing the structure‐related polycyclic compounds. [ABSTRACT FROM AUTHOR]

Herein, we report a method that provides an array of benzocyclobutanol and benzocyclobutylamine derivatives with broad substrate scope and good functional group tolerance under mild reaction conditions. The reaction proceeds by engaging triplet biradical atom transfer of olefinic compounds in the activation of remote C(sp3)−H bonds upon visible‐light irradiation. The reaction mechanism involves the generation of triplet excited state of diarylethylene derivative and subsequent HAT process, and then the further ring‐closing reaction affording the product via an electrocyclization process. The plausible mechanism is supported by control and deuterium labeling experiments, kinetic analysis, and DFT calculations. [ABSTRACT FROM AUTHOR]

A thermally‐induced intramolecular [4+2] cycloaddition reaction of allylamino‐ or allyloxy‐tethered alkylidenecyclopropanes has been reported in this paper, giving a new protocol for the rapid construction of polycyclic skeleton molecules in moderate to excellent yields with a broad substrate scope. On the basis of control experiments and DFT calculations, we disclosed that the reaction proceeded through a [4+2] cycloaddition and trace of water assisted 1,3‐H shift process to give the target product. [ABSTRACT FROM AUTHOR]

Employing silver/rhodium relay catalysis strategy, an intramolecular electrophilic cyclization and C−H activation followed by cascade hydrogenation and reductive amination has been developed. The acylmethylated isoquinoline derivatives could be afforded with broad substrate scope in 23–88% yields, which could be further transformed to the core skeleton of hexahydrodibenzo[a,g]quinolizine as drug‐candidates. Moreover, this reaction was achieved in a gram‐scale. A reasonable reaction mechanism has been proposed based on a series of control and KIE experiments. [ABSTRACT FROM AUTHOR]

Chiral tertiary phosphines are versatile Lewis base catalysts capable of promoting a wide range of asymmetric reactions. In particular, the recent designed chiral phosphines based on the concept of bi‐/multifunctionality have been demonstrated to be effective catalysts for many types of asymmetric reactions such as (aza)‐MBH reaction/RC reaction, cycloaddition reaction, domino reaction, nucleophilic addition reaction, etc. This review summarizes the recent advances in this field and highlights the selected significant achievements. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A RhIII/AgI relay‐catalyzed C(sp2)—H coupling of indoles with triarylhexahydrotriazine (THT) is reported in this context. Upon merging RhIII‐catalyzed C(sp2)—H bond activation and silver promoted THT dissociation, an efficient indole's C3 aminomethylation protocol is uncovered, providing C3 aminomethyl indoles in good yields and exhibiting potential applications for the synthesis of complicated bioactive compounds. We revealed the C3‐selectivity of this reaction through a detailed mechanistic investigation. Meanwhile, during the examination of the reaction conditions, we discovered another [4+2] cycloaddition pathway to afford tetrahydro‐indolo[3,2‐c]quinoline scaffold products via silver or Lewis acid catalysis. [ABSTRACT FROM AUTHOR]

The spirooxindole unit is one of the most widely investigated compound skeletons existing in numerous natural and pharmaceutical molecules. Thus, a large number of synthetic methodologies have already been reported to construct such a core structure. The trifluoromethyl group is another privileged unit in organic chemistry. The introduction of a CF3 group to an organic framework can significantly improve the properties of the molecule. In this context, an efficient approach for the construction of trifluoromethyl‐containing spirooxindoles becomes a promising research direction among communities of industry and academia. In this Minireview, recent advances in the construction of trifluoromethyl‐containing spirooxindoles have been summarized and discussed. In addition, representative synthetic methodologies and the corresponding reaction mechanisms have been described as well. [ABSTRACT FROM AUTHOR]

A dimerization and cyclization cascade reaction of 2‐sulfonaminoacrylates catalyzed by K2CO3 provides dihydro‐2‐oxopyrrole (DPO) derivatives. This straightforward and atom‐economic transformation features a simple experimental operation with easily available starting materials, a broad substrate scope as well as good functional group tolerance. The desired DPO building blocks are obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]

A phosphine‐catalyzed intermolecular annulation reaction of functionalized ortho‐aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2‐alkynylquinolines and benzo‐fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. [ABSTRACT FROM AUTHOR]

A catalyst‐free self‐catalyzed [3+2] cycloaddition reaction of 3‐isothiocyanato oxindoles with vinylpyridines has been established, affording the desired products in high yields (up to 97 %) with moderate to good diastereoselectivities (up to 11:1) under mild conditions. The reaction mechanism has been investigated by control experiments, DFT calculations of pKa values and the kinetic studies, revealing that this reaction featured the mutual activation between 3‐isothiocyanato oxindole and vinylpyridine to generate the reactive species. Furthermore, these products could be easily transformed into the corresponding methylated and hydroxylated products under basic conditions. [ABSTRACT FROM AUTHOR]

An efficient temperature‐dependent organocatalyzed asymmetric formal [3+2] cycloaddition reaction of α‐substituted isocyanoacetates to β‐trifluoromethylated enones by cinchona alkaloid‐derived squaramide has been investigated, affording the optically active trifluoromethylated 2‐pyrrolines in excellent yields (up to 98 %) and high stereoselectivities (>20:1 dr, up to >99 % ee) under mild conditions. [ABSTRACT FROM AUTHOR]

Abstract: A catalyst‐free self‐catalyzed [3+2] cycloaddition reaction of isatin‐derived α‐(trifluoromethyl)imines with vinylpyridines is reported. The reaction offers a straightforward and atom‐economical procedure for the preparation of a series of 5′‐trifluoromethyl‐spiro[pyrrolidin‐3,2′‐oxindoles] in excellent yields and diastereoselectivities. The reaction mechanism has been investigated by control experiments, DFT calculation of pKa values and the kinetic profiles, revealing that this reaction featured the mutual activation between isatin‐derived α‐(trifluoromethyl)imines and vinylpyridine to generate the reactive species. [ABSTRACT FROM AUTHOR]

Abstract: A facile synthesis of benzonitriles via a base‐promoted tandem cyclization reaction of α,β‐unsaturated enones having electron‐withdrawing group (EWG) and 2‐acyl‐acrylonitriles was developed. This new synthetic method to access benzonitriles is suitable for a wide range of substrates. A plausible reaction mechanism is proposed on the basis of previous literature and our own investigations. [ABSTRACT FROM AUTHOR]

In this paper, we disclose a novel strategy for the phosphine-catalyzed cycloaddition/SN2 substitution domino reaction, giving functionalized O-bridged benzoazepine and benzoxazepine derivatives in moderate to good yields. Changing the N-H protecting group of ortho-aminotrifluoroacetophenone derivatives gave different bridged-ring products in one step. [ABSTRACT FROM AUTHOR]

A one-step stereoselective synthetic method of 14-membered aza-macrocyclic dimers has been developed by a Lewis acid-catalyzed ring-opening and intermolecular cyclization reaction of aniline-tethered alkylidenecyclopropanes, affording 14-membered aza-macrocyclic dimers (mainly as E-configuration) in moderate to good yields under mild conditions. [ABSTRACT FROM AUTHOR]

A new zwitterion generated from different electron-deficient alkenes and phosphines has been designed and its reactivity was explored. We demonstrated that this new zwitterion directed a novel [2+1+2] cycloaddition reaction between vinylpyridines and isatin-derived electron-deficient alkenes, affording spirocyclopenteneoxindole derivatives containing three stereocenters in moderate to good yields with good diastereoselectivities. A plausible mechanism has been proposed relying on preliminary mechanistic investigations and supported by theoretical calculations. [ABSTRACT FROM AUTHOR]

Gold(I)-catalyzed cycloisomerization of ortho-(propargyloxy)arenemethylenecyclopropanes afforded two different types of products, that is, products of methylenecyclopropane migration and cycloisomerization products of the methylenecyclopropane moiety, controlled jointly by electronic and steric effects of the adjacent substituents. Furthermore, the corresponding cycloisomerization products could be also produced in an enantiomerically enriched manner. [ABSTRACT FROM AUTHOR]

An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6- exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions. [ABSTRACT FROM AUTHOR]

A facile synthetic method has been developed to access alkylidenephthalan and alkylidenethiophthalan derivatives through the cyclization of N-sulfonyl-1,2,3-triazoles in a rhodium(II)-catalyzed rearrangement. [ABSTRACT FROM AUTHOR]

A novel cinchona-alkaloid-derived organocatalyst has been developed to catalyze the asymmetric regioselective [3+2] cycloaddition of 3-isothiocyanato oxindoles with dibenzylidene ketones. A series of spirooxindole enols could be obtained in high yields with good-to-excellent diastereo- and enantioselectivities. [ABSTRACT FROM AUTHOR]

An effective one-pot procedure for the synthesis of phenanthridine derivatives containing N- or O-heterocycles has been developed through a two-step rhodium-catalyzed [2+2+2] cycloaddition and gold-catalyzed heterocyclization under mild conditions. The substrate scope has been investigated and a plausible reaction mechanism has been proposed on the basis of control experiments and previous literature reports. [ABSTRACT FROM AUTHOR]

The highly efficient organocatalytic enantioselective [3+2] cyclization of 3-isothiocyanato oxindoles with trifluoromethylated 2-butenedioic acid diesters for the synthesis of spirooxindoles possessing a CF3-containing quaternary carbon stereocenter was explored. An enantiodivergent approach for the synthesis of spirooxindoles by regulation of the temperature was demonstrated at different temperatures. The outcome of the reaction featured high diastereo- and enantioselectivities. Several interesting enantioenriched spirooxindole derivatives bearing a trifluoromethyl quaternary carbon stereocenter were synthesized from the products of this reaction. [ABSTRACT FROM AUTHOR]

RhII-catalyzed intermolecular [3+2] cycloaddition of 2 H-azirines with N-sulfonyl-1,2,3-triazoles is disclosed, in which a series of fully functionalized pyrroles is produced via rhodium azavinyl carbene intermediates. A distinct feature of this reaction is that the azavinyl carbene serves as a [2 C] equivalent, instead of as [1 C] or aza-[3 C] synthons, which have been reported previously in cyclopropanations and [3+ n] cycloadditions. Moreover, this methodology has also been successfully applied in the total synthesis of URB447 as well as the formal synthesis of Atorvastatin (Lipitor). [ABSTRACT FROM AUTHOR]

Gold- and silver-catalyzed novel intramolecular cycloisomerizations of nitrogen or carbon-tethered indolylcyclopropenes to furnish biologically and pharmaceutically valuable azepino-[4,5- b]indole and spiro[indoline-3,4′-piperidine] derivatives have been developed. Both reactions exhibit high chemoselectivity and stereospecificity through completely different reaction pathways. Based on mechanistic studies, it is well demonstrated that gold and silver catalysts act differently to promote the anti- and syn-addition and the steric effect of the catalysts play an important role to switch the addition mode, affording the catalyst-controlled-divergent synthesis. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric [3+2] cycloadditions of C,N-cyclic azomethine imines with δ-substituted allenoates have been developed in the presence of ( S)-Me-f-KetalPhos, affording functionalized tetrahydroquinoline frameworks in good yields with high diastereo- and good enantioselectivities under mild condition. The substrate scope has been also examined. This is the first time that δ-substituted allenoates have been applied as a δ,γ-CC bond participated C2 synthon in asymmetric synthesis. [ABSTRACT FROM AUTHOR]

A highly efficient palladium(0)-catalyzed asymmetric [3+2] cycloaddition using 3-diazooxindoles serving as dipolarophiles affords functionalized pyrazolidine derivatives in an atom-economical way. In addition, by trapping the pyrazolidine derivatives with maleimides, the corresponding spiropyrazolidine oxindoles containing multiple stereogenic centers have been obtained in high yields along with moderate to good levels of diastereoselectivity and enantioselectivity under mild conditions. Thus, a novel three-component one-pot tandem reaction has been developed. [ABSTRACT FROM AUTHOR]

A novel phosphine-catalyzed [4+1] annulation of maleimides with 4,4-dicyano-2-methylenebut-3-enoates has been developed to afford spirocyclic products, and the maleimides serves as C1 synthons. Moreover, a phosphine-catalyzed formal [3+2] annulation between 4,4-dicyano-2-methylenebut-3-enoates and maleic anhydride has been also achieved, and maleic anhydride behaved as a C3 synthon in the reaction, thus efficiently affording the functionalized cyclopentenones. A stable phosphinium-containing zwitterionic compound is the key reactive intermediate in both annulations and was successfully isolated. Plausible mechanisms have been proposed on the basis of control experiments and deuterium-labeling experiments. [ABSTRACT FROM AUTHOR]

A highly regio- and stereoselective synthesis of bispirooxindoles by 1,3-dipolar cycloaddition of in situ generated azomethine ylides from isatin and proline to different electron-deficient alkenes has been developed. The synthesis affords the desired bispiro scaffold compounds in excellent yields with high regioselectivity under mild conditions. The stereochemistry was determined by single-crystal X-ray analysis. [ABSTRACT FROM AUTHOR]

A novel type of yne-vinylidenecyclopropanes (VDCPs) has been synthesized and applied in gold-catalyzed cycloisomerization reactions. It was found that these compounds can undergo an intramolecular cycloisomerization and perform as a three-carbon synthon for [3+2] cycloaddition under gold catalysis to give fused [4.3.0] and [5.3.0] bicyclic derivatives and VDCP rearranged products in moderated to good yields under mild conditions. The substrate scope of these novel transformations has been explored and plausible reaction mechanisms have been presented on the basis of deuterium labeling experiments and DFT calculations. [ABSTRACT FROM AUTHOR]

The first highly enantioselective formal [4+2] tandem cyclizations between isatylidenemalononitriles and activated dienes catalyzed by bifunctional chiral phosphine catalysts have been developed, yielding multistereogenic spirocyclic oxindoles in high yields and excellent optical purity. This reaction is accomplished via a tandem Rauhut-Currier/Michael/Rauhut-Currier reaction sequence. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric [3+2] cycloaddition of (3-isothiocyanato)oxindoles with azodicarboxylates has been explored in the presence of (DHQD)2PHAL. It affords spirooxindoles having two heterocycles at their C3′-position in excellent yields, with high enantioselectivities, and under mild conditions within 5 min. Moreover, another spirooxindole derived from the reaction of (3-isothiocyanato)oxindole with two molecules of azodicarboxylate could also be formed in excellent yields with the same high enantioselectivities under the standard conditions. [ABSTRACT FROM AUTHOR]

An AuI/AuIII catalytic system was found to be effective for the cascade oxidative arylation and cyclization of allenoates with arylboronic acids to give the corresponding cyclic adducts in moderate yields. This reaction system constitutes a new method for the synthesis of β-aryl-γ-butenolides under mild conditions. Based on the previous mechanistic studies, a proposed AuI/AuIII redox catalytic cycle has been outlined. [ABSTRACT FROM AUTHOR]

A novel phosphine-promoted intramolecular cyclization of dicyclopropenones 1 has been described in this contribution. A variety of 2,3-dihydro-1 H-indene-4,6-diol derivatives 2 and hexahydropentalen-2-one derivatives 3 were obtained selectively in moderate to good yields under mild conditions through different phosphine-promoted reactions. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric [4+2] annulations of isatins with but-3-yn-2-one catalyzed by the Cinchona alkaloids-derived oragnocatalyst (DHQD)2PHAL have been developed in the presence of 3.0 equivalents of D-diethyl tartrate in the mixed solvent (diphenyl ether/diethyl ether=1/1) or a slightly modified one, affording the corresponding substituted spiro[indoline-3,2′-pyran]-2,4′(3′ H)-diones in good to excellent yields with high enantioselectivities under mild conditions. [ABSTRACT FROM AUTHOR]

Diynes containing a cyclopropane group smoothly undergo a novel intramolecular and stereoselective cascade addition/cyclization reaction to produce the corresponding 1-methyleneindene derivatives in moderate to good yields. This interesting transformation is mediated by Grignard reagent/CuI with LiCl as an additive under mild conditions. The obtained product can easily be further functionalized through cyclopropyl ring opening. A plausible reaction mechanism has also been presented on the basis of deuterium labeling and control experiments. [ABSTRACT FROM AUTHOR]

A novel Cinchona alkaloid-derived organocatalyst having stronger hydrogen-bonding donors that catalyzes the asymmetric [3+2] cycloaddition of 3-isothiocyanatooxindoles with allenic esters or 2-butynedioic acid diesters has been developed, affording functionalized spirooxindole derivatives in high yields along with good to excellent enantioselectivities under mild conditions. We also found that by changing the ratio of the substrates, different spirooxindole derivatives could be obtained in high yields along with good to excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

Efficient cyclization of 1-(indol-3-yl)-3-alkyn-1-ols in the presence of a cationic gold(I) complex, leading to annulated or specific substituted carbazoles, was observed. Depending on the reaction conditions and substitution pattern, divergent reaction pathways were discovered, furnishing diversified carbazole structures. Cycloalkyl-annulated [ b]carbazoles are obtained through 1,2-alkyl migration of the metal-carbene intermediates; cycloalkyl-annulated [ a]carbazoles are formed through a Wagner-Meerwein-type 1,2-alkyl shift; carbazole ethers are constructed through ring-opening of the cyclopropyl group by nucleophilic attack of water or an alcohol. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A RhIII/AgI relay‐catalyzed C(sp2)—H coupling of indoles with triarylhexahydrotriazine (THT) is reported in this context. Upon merging RhIII‐catalyzed C(sp2)—H bond activation and silver promoted THT dissociation, an efficient indole's C3 aminomethylation protocol is uncovered, providing C3 aminomethyl indoles in good yields and exhibiting potential applications for the synthesis of complicated bioactive compounds. We revealed the C3‐selectivity of this reaction through a detailed mechanistic investigation. Meanwhile, during the examination of the reaction conditions, we discovered another [4+2] cycloaddition pathway to afford tetrahydro‐indolo[3,2‐c]quinoline scaffold products via silver or Lewis acid catalysis. [ABSTRACT FROM AUTHOR]

The epoxide opening with BF3·OEt2 followed by cleavage of the aldehyde group of the resulting β-ketoaldehyde furnishes deoxybenzoins which give the title furans after HBr-promoted ring closure. [ABSTRACT FROM AUTHOR]

A Rh(II)-catalyzed tandem intramolecular cyclization of aromatic aldehydes and ketones having a (1-sulfonyl-1,2,3-triazolyl)methoxy side chain is developed to allow a novel synthesis of the title compounds (II), (IV), and (VI). [ABSTRACT FROM AUTHOR]

The synthesis of the title compounds involves asymmetric [3 + 2] cycloaddition of 3-diazooxindoles with vinylcyclopropanes. [ABSTRACT FROM AUTHOR]

The title cyclization is accomplished via a tandem Rauhut-Currier/Michael/Rauhut-Currrier reaction sequence to give spirocyclic oxindoles in high yields along with excellent enantio- and diastereoselectivities. [ABSTRACT FROM AUTHOR]

In the title compound, C10H20O5, the six-membered ring adopts a slightly twisted chair conformation. The crystal packing is stabilized by inter­molecular O—H⋯O inter­actions. [ABSTRACT FROM AUTHOR]

An oxidative cyclization of N-alkenyl formamidines leads to the corresponding cyclic formamidinium salts. [ABSTRACT FROM AUTHOR]

An abstract of the article "Palladium-Catalyzed Cascade Cyclization of Allylamine-Tethered Alkylidenecyclopropanes: Facile Access to Iodine/Difluoromethylene- and Perfluoroalkyl-Containing 1-Benzazepine Scaffolds" by Liu-Zhu Yu and colleagues is presented.

A novel and efficient synthetic protocol to access furoquinoline and thienoquinoline derivatives is presented. [ABSTRACT FROM AUTHOR]

The newly developed facile procedure allows for the synthesis of 3-substituted isoquinoline and dihydroisoquinoline derivatives which are difficult to access by other known methods. [ABSTRACT FROM AUTHOR]

A variety of axial chiral NHC-oxazoline gold(I) complexes are synthesized and combined with Selectfluor in situ to catalyze the oxidative cycloaddition reaction of enynone and alkenes with air as green oxidant. [ABSTRACT FROM AUTHOR]