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Herein, previously unreported trimethylindolenines serving as useful C–N synthons in [3+2] cycloaddition reactions of donor–acceptor 3-isothiocyanato oxindoles to build a library of spiro[oxindole-thioxoimidazolidine-indoline] hybrids are described. A wide range of intriguing and complex products bearing three pharmacophores and three adjacent quaternary stereocentres were smoothly afforded in up to 92% yield, >20 : 1 dr, under catalyst-free conditions. Moreover, this strategy further expands the skeletal diversity of polyheterocycles, which will aid the search for new bioactive molecules. [ABSTRACT FROM AUTHOR]

The H2O-promoted controllable synthesis of diverse nitrogen heterocycles from readily available feedstocks was developed by a hydride transfer strategy. A variety of 3-carboxyl and 3-acyl substituted tetrahydroquinolines and 3,4-dihydroquinolin-2(1H)-ones were obtained via cascade Knoevenagel condensation/[1,5]-hydride transfer/cyclization/hydrolysis/decarboxylation and cascade Knoevenagel condensation/[1,5]-hydride transfer/N-dealkylation/N-acylation processes, respectively. In addition, the synthetic utility of the methodology and mechanistic studies were also well presented. [ABSTRACT FROM AUTHOR]

Herein, previously unreported Fischer's base reactants serving as useful 2C building blocks in (3+2) cycloaddition reactions to build a library of bispiro[Fischer's base-oxindole] hybrids are described. These structurally intriguing products containing three adjacent quaternary stereocentres were smoothly afforded in up to 82% yield and >20 : 1 dr under catalyst-free conditions. Notably, the present protocol firstly employs 3-isothiocyanato oxindole serving as an acceptor and then as a donor in the formal (3+2) cycloadditions, allowing practical, straightforward access to structurally diverse cycloadducts. This work expands the applicability scope of 3-isothiocyanato oxindoles, which have been limited to behaving as donor/acceptor-based synthons in cycloadditions in previous work. [ABSTRACT FROM AUTHOR]

A substrate-dependent, highly β-regioselective one-pot multicomponent 1,3-dipolar cycloaddition reaction of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles with azomethine ylides (thermally generated in situ from ninhydrin and sarcosine) is reported for the first time, furnishing a library of biologically useful bispiro[oxindole-isoxazole-indandione] hybrids. Target novel and structurally complex compounds have been obtained in good yields and diastereoselectivities (up to 91% yield and 20 : 1 dr) with two adjacent spiro quaternary centres. Furthermore, the described method, which is different from our previous work of α-regioselective cycloaddition of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles, is a highly β-regioselective cycloaddition. The newly synthesized compounds potently inhibited the proliferation of various cancer cell lines. The most potent compound 4ah could induce the apoptosis of K562 cells through a caspase-dependent and -independent pathway. [ABSTRACT FROM AUTHOR]

Herein, a highly efficient strategy that allows the diverse synthesis of a library of structural bispiro[butyrolactone–pyrrolidine–indanedione] hybrids is achieved effectively for the first time by means of 1,3-dipolar cycloadditions of α,β-unsaturated butyrolactones/valerolactones as dipolarophiles with azomethine ylides (thermally generated in situ from ninhydrin and proline or thioproline) via an exo′-transition state. Potentially bioactive target compounds have been obtained in good yields and diastereoselectivities (up to 89% yield and all cases >20 : 1 dr). [ABSTRACT FROM AUTHOR]

Inspired by the chemistry and biology of butyrolactones, pyrrolidines, and chromanones, we successfully developed a simple domino 1,3-dipolar cycloaddition of homoserine-lactone-derived azomethine ylides for the construction of biologically important spiro[butyrolactone–pyrrolidine–chromanone] hybrids in the presence of Et3 N as a catalyst under mild conditions. The reaction is based on the application of carboxylic-acid-activated chromones as dienophiles, followed by a decarboxylation process. This reaction displayed good substrate tolerance and gave the desired products in moderate to good yields with high diastereoselectivities (up to 85% yield and >20:1 diastereomeric ratio) via an exo -transition state. This is the first example of an introduction of a chromanone moiety into a spiro[butyrolactone-pyrrolidine] framework, which might be valuable in medicinal chemistry. [ABSTRACT FROM AUTHOR]

Inspired by the chemistry and biology of chromone, a method for the construction of spirooxindole‐based tetrahydrocyclopenta[b]chromanones is reported with good regio‐ and diastereoselectivity (all cases >20:1 dr) and moderate yields (up to 67%). This method leads to the construction of four contiguous stereogenic tertiary centers and one spiro quaternary center via a one‐step γ‐regioselective cascade [3+2] cycloaddition of an oxindole‐chromone synthon with 3‐methyl‐4‐nitro‐5‐alkenyl‐isoxazole. [ABSTRACT FROM AUTHOR]

The first example of a bifunctional donor–donor 3C synthon in situ from activated methine (methyleneindolinone and methylenebenzofuranone) with nitromethane through a [2+1] Michael addition, which further directed the following organocascade Michael/Henry cycloaddition reaction in a one-pot operation is developed, serving as a fruitful strategy for facile access to optically active and structurally diverse hexahydroxanthones with up to six contiguous stereocenters, including a quaternary one. A series of diversely functionalized products are smoothly obtained with up to 76% yield, >20 : 1 d.r. and 98% ee from simple and readily available starting materials. In addition, this is the first example of 3-formyl chromone as an acceptor–acceptor 3C building block, and also the first asymmetric catalytic construction of six vicinal stereogenic centers on a hexahydroxanthone scaffold. [ABSTRACT FROM AUTHOR]

The first example of bifunctional oxindole‐chromone C3 synthon directed organocatalytic cascade cycloaddition reaction is developed, serving as a fruitful strategy for the facile access of optically active tetrahydrocyclopenta[b]chromanone bearing one spirooxindole with five contiguous stereocenters. All the products are smoothly obtained with up to 83% yield, >20:1 d.r. and >99% ee. This is also the first asymmetric catalytic construction of tetrahydrocyclopenta[b] chromanone and tetrahydrocyclopenta[b]chromanone‐spirooxindole scaffold, thus to facilitate the search for new bioactive entities. [ABSTRACT FROM AUTHOR]

A new method was developed for the facile one-pot multicomponent construction of heterocycle-fused spiro compounds containing chromanone and pyrrolidinyl spirooxindoles, two potential pharmacophores, in one molecule through a decarboxylative 1,3-dipolar [3 + 2] cycloaddition reaction of carboxylic acid group-activated chromones 1 with isatin-derivated azomethine ylides based on molecular hybridization strategy. A wide variety of products with three contiguous stereocenters including a spiro quaternary stereocenter were smoothly prepared with high efficiency (up to 87% yield and 20:1 diastereomeric ratio). This method could offer libraries of architecturally diverse and multiple pharmacore collections, potentially useful in medicinal chemistry. [ABSTRACT FROM AUTHOR]

A highly efficient strategy for stereocontrolled construction of potentially bioactive and structurally rigid isoxazole-fused spirocyclohexane oxindole-based hexahydroxanthones via an organocatalytic domino Michael/Michael cycloaddition of multifunctional chromone-based oxindole as a 4C building block and 3-methyl-4-nitro-5-alkenyl-isoxazole as an activated Michael acceptor is reported. Complex and skeleton-diversified hexahydroxanthones bearing five continuous stereocenters including one spiro quaternary carton center were smoothly afforded in up to 92% yield, >20:1 d.r. and >99% ee. Further transformation of the product into other potentially bioactive molecules has also been demonstrated. This method could also forge the libraries of medicinally relevant molecules with skeletal diversity, thus to facilitate the search for new bioactive entities. [ABSTRACT FROM AUTHOR]

A new methodology was developed for the synthesis of 3,3′-pyrrolidinyl-dispirooxindoles 3 through a 1,3-dipolar cycloaddition event of isatylidenyl-chromanones 2 with azomethine ylides (thermally generated in situ from isatins and sarcosine). The method gives an easy access to a series of highly functionalized products containing three consecutive stereocenters and vicinal spiroquaternary stereocenters fused in one ring structure with 15 examples in high yields (up to 82% yield) and good diastereoselectivity (up to >20:1), which makes possible the synthesis of libraries under similar circumstances. Moreover, the current method provides a convenient approach for the efficient incorporation of two biologically important scaffolds (chromanone and 3,3′-pyrrolidinyl-dispirooxindoles). X-ray diffraction studies of one of the cycloadducts proved the structure and regiochemistry of the cycloaddition. In particular, their biological activity against human leukemia cells K562 and normal L929 cells has been evaluated. These results suggested that 3,3′-pyrrolidinyl-dispirooxindoles 3 may be potential leads for further biological screenings. [ABSTRACT FROM AUTHOR]

Described herein is the development of a facile and efficient methodology for the synthesis of novel turmerone motif-fused 3,30-pyrrolidinyl-dispirooxindoles 3-5 via a multicomponent 1,3-dipolar cycloaddition of dienones 2 with azomethine ylides (thermally generated in situfrom isatins and proline or thioproline or sarcosine). Products bearing four or three consecutive stereocenters consist of two oxindole moieties and a pyrrolidinyl core, including vicinal spiroquaternary stereocenters fused in one ring structure were smoothly obtained in high yields (up to 93% yield) with good diastereoselectivity (up to >20:1). Another valuable application of this method was for the design of new hybrid architectures for biological screening through the adequate fusion of these sub-units of turmerone and 3,30-pyrrolidinyl-dispirooxindole, generating drug-like molecules. [ABSTRACT FROM AUTHOR]

Reported is a facile and efficient methodology toward the synthesis of novel pyrimidine-fused spiropyrrolidine oxindoles via a multicomponent 1,3-dipolar cycloaddition reaction of pyrimidine-fused 3-alkenyloxindoles 1 with azomethine ylides (thermally generated in situ from sarcosine and formaldehyde). Products bearing adjacent quaternary–tertiary centers were smoothly obtained in high yields (up to 90% yield) with good diastereoselectivity (up to >20:1). In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human lung cancer cells A549, human prostate cancer cells PC-3, and human leukemia cells K562 by the MTT-based assays, using the commercially available broad-spectrum anticancer drug of Cisplatin as a positive control. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these three cell lines of K562, PC-3, and A549, showed comparably potent or even more potent than the positive control of Cisplatin (up to 3.0 times), and indicated that novel pyrimidine-fused spiropyrrolidine oxindoles may be potential leads for further biological screenings and may generate drug-like molecules. [ABSTRACT FROM AUTHOR]

Developed herein is a facile and efficient methodology toward the synthesis of novel turmerone motif-fused spiropyrrolidine oxindoles via a multicomponent 1,3-dipolar cycloaddition event of dienones 2 with azomethine ylides (thermally generated in situ from isatin derivatives and sarcosine). Products bearing adjacent quaternary–tertiary centers were smoothly obtained in high yields (up to 93% yield) with good diastereoselectivity (up to >20:1). In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays, using the commercially available standard drug of Cisplatin as a positive control. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these two cell lines of K562 and A549, showed comparably potent or even more potent than the positive control of Cisplatin (up to 5.1 times), and indicated that novel turmerone motif-fused spiropyrrolidine oxindoles may be potential leads for further biological screenings and may generate drug-like molecules. [ABSTRACT FROM AUTHOR]

CO 2 -epoxide cycloaddition represents one of most attractive approaches for chemical fixation and utilization of CO 2 , but highly efficient and fully heterogeneous green catalysis is still challenging. Ionic metal-organic frameworks (IMOFs) are nice porous matrices heterogenizing the essential free nucleophilic anions and meanwhile providing Lewis acids, but the catalytic efficiency has been limited for low anion content and lack of auxiliary catalytic sites. In this work, we report stepwise optimization of IMOF catalysts by integrating multiple catalytic sites into MIL-101. Various monocationic IMOFs with quaternary ammonium and bromide anions were prepared by facile alkyne-azide click chemistry. Different numbers of hydroxyl groups were introduced in this ionization step to optimize the activity. To introduce more anions, dicationic IMOFs were created by a second ionization step, N -quaternization of triazolyl to triazolium. By the stepwise ionization and functionalization, we demonstrated the synergic catalytic effects among different sites, the impacts of hydroxyl/bromide content, and the size effect of the cationic group. The optimal IMOFs are superior to previous ionic heterogeneous catalysts in absence of cocatalysts. In particular, the dicationic catalyst can quantitatively convert epichlorohydrin to the carbonate within 1 h at 1 MPa CO 2 and 80 °C, the apparent turnover frequency being up to 478 h−1. The highly active and selective, fully heterogeneous and recyclable catalyst has the appeal for practical applications. [Display omitted] Stepwise modification of MIL-101 with dual cationic groups allows integration of three types of active sites (Lewis acid, hydrogen-bonding hydroxyl group and nucleophilic bromide anion) in one material. The sites act in synergy with compromise with steric effects to afford ionic heterogeneous catalysts with outstanding activity for conversion of CO 2 under solvent- and cocatalyst-free mild conditions. • Mono-/dicationic multifunctional ionic MOFs were designed to catalyze the CO 2 conversion. • Grafting hydroxyl groups enhances the catalytic activity but the enhancement is limited by steric effects. • Increasing anion content by cationizing existent groups leads to significant activity enhancement. • The hydroxyl-functionalized bicationic MOF shows excellent catalytic activity and heterogeneity. [ABSTRACT FROM AUTHOR]

A mild and efficient method for the construction of pyrrolidinyl spirooxindoles via a 1,3-dipolar cycloaddition reaction of (E)-N-Boc-3-alkylidene-indolin-2(3H)ones with azomethine ylides has been established. The presence of anN-Boc group in the indolin-2(3H)ones obviously increased the activity and stereoselectivity of the reaction, affording the desired pyrrolidinyl spirooxindoles4with up to 85% yield and up to >99/1drvalue. Furthermore, the antibacterial activity of these compounds againstStaphylococcus aureus(ATCC-25825) has been tested at minimum concentration, and some of them exhibit moderate antibacterial activity. [Supplementary materials are available for this article. Go to the publisher's online edition ofSynthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] [ABSTRACT FROM AUTHOR]

Facile and efficient methodology for the synthesis of novel turmerone motif-fused spiropyrrolidine oxindoles via a multicomponent 1,3-dipolar cycloaddition reaction of dienones with azomethine ylides is reported. [ABSTRACT FROM AUTHOR]

Some of the new compounds (IV) exhibit moderate antibacterial activity against S. [ABSTRACT FROM AUTHOR]

Structurally diverse 3,3′-thiopyrrolidonyl spirooxindoles bearing three contiguous stereogenic centers can be smoothly prepared via domino Michael/cyclization reaction using quinine as chiral catalyst. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Diversity-oriented synthesis. • Four contiguous stereocenters. • A carboxylic acid-activation and then decarboxylation strategy. Abstract A new methodology was developed for the highly efficient one-pot multicomponent synthesis of chromanone-based 3,3′-pyrrolidinyl-spirooxindoles via a 1,3-dipolar cycloaddition reaction of chromones 1 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Another valuable application of this method was for the less reactive chromone through a carboxylic acid-activation and then decarboxylation strategy, which enabled diversity-oriented synthesis of complex pirooxindoles bearing four contiguous stereocenters (one of which is a spiro quaternary stereocenter) with high efficiency and stereoselectivity (up to 90% yield and 20:1 d.r.). This protocol could provide libraries of stereochemically rich and multiple pharmecore collections, that will help in search for new drug-like molecules. [ABSTRACT FROM AUTHOR]

Developed herein is a diversity-oriented one-pot multicomponent synthesis of polycyclic 3,3′- pyrrolidinyl-dispirooxindoles 3 via a multicomponent 1,3-dipolar cycloaddition event of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles 2 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Products bearing four consecutive stereocenters consist of two oxindole moieties and a polycyclic pyrrolidinyl core, including vicinal spiroquaternary stereocenters fused in one ring structure were smoothly obtained in high yields (up to 85% yield) with good diastereoselectivity (up to >20:1). Valuable features of this method were application of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles as 1,3-dipolarophiles and the design of new hybrid architectures for biological screenings through the adequate fusion of these sub-units of isoxazole and 3,3′-pyrrolidinyl-dispirooxindole, generating drug-like molecules. [ABSTRACT FROM AUTHOR]

Described herein is a facile and efficient methodology toward the synthesis of Morusin scaffolds and Morusignin L scaffolds 4 – 9 and 12 via a novel three-step approach (Michael addition or prenylation, cyclization and cyclization) and use a rapid, microwave-accelerated cyclization as the key step. Furthermore, their biological activities have been preliminarily demonstrated by in vitro evaluation for anti-osteoporosis activity. These Morusin, Morusignin L and newly synthesized compounds 5b , 6a , 8e , 8f greatly exhibited the highest potency, especially at the 10 −5 mol/L (P < 0.01), and had good in vitro anti-osteoporosis activities using the commercially available standard drug Ipriflavone as a positive control. The mechanisms associated with anti-osteoporosis effects of these compounds may be through the inhibition of TRAP enzyme activity and bone resorption in osteoclasts, and promotion effect of osteoblast proliferation in vitro . The results indicated that Morusin scaffolds and Morusignin L scaffolds may be useful leads for further anti-osteoporosis activity screenings. [ABSTRACT FROM AUTHOR]

Described herein is a facile and efficient methodology for diversity-oriented one-pot multicomponent synthesis of 3-aminomethyl quaternary carbon oxindole fused five-membered carbocyclic spirooxindoles 5 via knoevenagel condensation/Michael/cyclization and then aminomethylation reaction. A wide variety of products with varying degrees of substitution around it, were obtained smoothly with high efficiency (up to overall yield 73% and >20:1 diastereoselectivity). In particular, their biological activities against these three cell lines K562, A549 and PC-3 have been evaluated. These results suggested that most of 3-aminomethyl quaternary carbon oxindole fused five-membered carbocyclic spirooxindoles 5 showed equipotent or more potent than the positive control of Cisplatin (up to 3.4 times). [ABSTRACT FROM AUTHOR]

A facile and efficient methodology was developed for the synthesis of isoxazole-fused spiropyrrolidine oxindoles 3–5 via a 1,3-dipolar cycloaddition reaction of 3-methyl-4-nitro-5-alkenyl-isoxazoles with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline or sarcosine). Products bearing adjacent quaternary-tertiary centers were smoothly obtained in high yields (up to 90% yield) with good diastereoselectivity (up to 20:1). Furthermore, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays using the commercially available standard drug Cisplatin as a positive control. These results suggested that most of isoxazole-fused spiropyrrolidine oxindoles 3–5 showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and that isoxazole-fused spiropyrrolidine oxindoles may be potential leads for further biological screening. [ABSTRACT FROM AUTHOR]

A facile and efficient methodology was developed for the synthesis of multifunctional polycyclic spiropyrrolidine oxindoles bearing mesityl oxide unit via a three-component 1,3-dipolar cycloaddition reaction of dienones 2 with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline). Products bearing adjacent four chiral carbon centers were smoothly obtained in high yields (up to 98% yield) with diastereoselectivities up to >20:1. Furthermore, the key structural characteristic of the products of such a reaction is the natural product ingredient turmerone motif fused at the 3-position of the spirooxindole core, with varying degrees of substitution around it. In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays, using the commercially available standard drugs Cisplatin as a positive control. These results suggested there is a trend that lipophilicity groups improve the potency, and also suggested an mesityl oxide moiety located in the polycyclic spiropyrrolidine oxindoles is beneficial for the activity. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and indicated that polycyclic spiropyrrolidine oxindole analogs bearing mesityl oxide unit may be potential leads for further antitumor activity screenings. [ABSTRACT FROM AUTHOR]

A new methodology was developed for the synthesis of spirocyclic oxindoles bearing polyfunctional dihydropyrrole units via an organocatalytic tandem Michael/cyclization sequence. Products bearing adjacent quaternary–tertiary stereocenters were smoothly obtained in high yields (up to 97% yield) with excellent diastereoselectivities up to >20/1. [ABSTRACT FROM AUTHOR]

Herein we successfully developed a domino [3 + 2] cycloaddition of isatin-based (trifluoromethyl)imine ylides with benzylidenechromanones for the construction of a series of biologically important and structurally diverse bispiro-[oxindole-pyrrolidine-chromanone]s incorporating a CF 3 motif under the organocatalyst DABCO catalysis. The reaction offers a straightforward and atom-economical procedure for the preparation of the desired products featuring four contiguous stereocenters including two vicinally spiro quaternary stereocenters in moderate to good yields with high diastereoselectivity via an exo-transition state (up to 91 % yield and >20:1 diastereomeric ratio). Of note, this is the first example of the introduction of CF 3 units into spirocyclic chromanone compounds, which might be valuable in medicinal chemistry. [Display omitted] • Potential biologically active molecules. • Diastereoselective and exo-selective 1,3-dipolar cycloaddition. • The first example of the introduction of CF 3 units into spirocyclic chromanones. [ABSTRACT FROM AUTHOR]

1,3-Dipolar cycloaddition of in situ thermally generated azomethine ylides with alkenyl substituted isoxazoles offers a convenient synthesis of fused spiropyrrolidine oxindoles in good diastereoselectivity. [ABSTRACT FROM AUTHOR]

A facile and efficient methodology is developed for the synthesis of multifunctional polycyclic spiropyrrolidine oxindoles via a three-component 1,3-dipolar cycloaddition reaction of dienones (III) with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline). [ABSTRACT FROM AUTHOR]