Morita Baylis Hillman Carbonates Research Articles

Sequential Assembly of Morita-Baylis-Hillman Carbonates and Activated ortho-Vinylbenzaldehydes To Construct Chiral Methanobenzo[7]annulenone Frameworks.

The α-regioselective asymmetric [3 + 2] annulation reaction of Morita-Baylis-Hillman carbonates from isatins and activated ortho-vinylbenzaldehyses was developed by the catalysis of a chiral tertiary amine. The sequential N-heterocyclic carbene-mediated intramolecular Stetter reaction was conducted to finally furnish the bridged 5,8-methanobenzo[7]annulen-9-one architectures incorporating a spirooxindole motif with excellent stereoselectivity.

Organocatalytic Synthesis of Sulfoximidoyl-Containing Carbamates from Sulfoximines and Morita-Baylis-Hillman Carbonates.

An unexpected substitution reaction providing sulfoximidoyl-containing carbamates was observed when Morita-Baylis-Hillman carbonates and NH-sulfoximines were mixed in acetonitrile at elevated temperature. Key ingredients were triethylamine and ortho-hydroxybenzoic acid, which both had to be present in catalytic quantities.

Phosphine-Catalyzed Domino [3 + 3] Cyclization of para-Quinamines with Morita-Baylis-Hillman Carbonates: Access to Hydroquinoline Derivatives.

A phosphine-catalyzed [3 + 3] cyclization strategy between para-quinamines and HCHO Morita-Baylis-Hillman (MBH) carbonates was discovered, delivering a series of highly functionalized hydroquinoline derivatives in moderate to good yields and excellent diastereoselectivity. Moreover, mechanistic insights, gram-scale experiments, and synthetic manipulations of the products were also discussed.

Asymmetric [3+2] Cycloaddition of Olefins with Morita–Baylis–Hillman Carbonates Catalyzed by BINOL-Based Bifunctional Phosphine

We have developed a series of novel BINOL-based phosphines. These bifunctional organocatalysts can be used in the [3+2] cycloaddition of electron-deficient olefins and Morita–Baylis–Hillman (MBH) carbonates. Moderate to excellent yields (up to >99%) and good to excellent enantioselectivities (up to 95% ee) can be obtained in the cycloaddition reaction of maleimides and MBH carbonates. The application of these novel phosphines can be further extended to the asymmetric synthesis of chiral spirooxindoles (up to 85% ee). The results in this study indicate that the BINOL moiety plays an important role in stereocontrol.

Auto‐Tandem Cooperative Catalysis Using Phosphine/Palladium: Reaction of Morita–Baylis–Hillman Carbonates and Allylic Alcohols

AbstractAuto‐tandem catalysis (ATC), in which a single catalyst promotes two or more mechanistically different reactions in a cascade pattern, provides a powerful strategy to prepare complex products from simple starting materials. Reported here is an unprecedented auto‐tandem cooperative catalysis (ATCC) for Morita–Baylis–Hillman carbonates from isatins and allylic carbonates using a simple Pd(PPh3)4 precursor. Dissociated phosphine generates phosphorus ylides and the Pd leads to π‐allylpalladium complexes, and they undergo a γ‐regioselective allylic–allylic alkylation reaction. Importantly, a cascade intramolecular Heck‐type coupling proceeds to finally furnish spirooxindoles incorporating a 4‐methylene‐2‐cyclopentene motif. Experimental results indicate that both Pd and phosphine play crucial roles in the catalytic Heck reaction. In addition, the asymmetric versions with either a chiral phosphine or chiral auxiliary are explored, and moderate results are obtained.

Auto‐Tandem Cooperative Catalysis Using Phosphine/Palladium: Reaction of Morita–Baylis–Hillman Carbonates and Allylic Alcohols

Auto-tandem catalysis (ATC), in which a single catalyst promotes two or more mechanistically different reactions in a cascade pattern, provides a powerful strategy to prepare complex products from simple starting materials. Reported here is an unprecedented auto-tandem cooperative catalysis (ATCC) for Morita-Baylis-Hillman carbonates from isatins and allylic carbonates using a simple Pd(PPh3 )4 precursor. Dissociated phosphine generates phosphorus ylides and the Pd leads to π-allylpalladium complexes, and they undergo a γ-regioselective allylic-allylic alkylation reaction. Importantly, a cascade intramolecular Heck-type coupling proceeds to finally furnish spirooxindoles incorporating a 4-methylene-2-cyclopentene motif. Experimental results indicate that both Pd and phosphine play crucial roles in the catalytic Heck reaction. In addition, the asymmetric versions with either a chiral phosphine or chiral auxiliary are explored, and moderate results are obtained.

Creation of bispiro[pyrazolone-3,3′-oxindoles] via a phosphine-catalyzed enantioselective [3 + 2] annulation of the Morita–Baylis–Hillman carbonates with pyrazoloneyldiene oxindoles

A [3 + 2] annulation between the Morita–Baylis–Hillman (MBH) carbonates and pyrazoloneyldiene oxindoles catalyzed by (S)-SITCP has been developed.

Enantioselective dearomative [3+2] cycloaddition of 2-nitrobenzofurans with aldehyde-derived Morita-Baylis-Hillman carbonates.

The phosphine-catalyzed asymmetric dearomative [3+2] cycloaddition of 2-nitrobenzofurans with aldehyde-derived Morita-Baylis-Hillman (MBH) carbonates or allenoate was developed. The reaction with MBH carbonates resulted in a series of cyclopentabenzofurans containing three contiguous stereocenters with good to high yields, diastereoselectivities and enantioselectivities. The use of allenoate also gave the target product with moderate enantioselectivity.

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita-Baylis-Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives.

An intriguing DABCO-catalyzed and DBU-promoted one-pot synthesis of an important class of (2-hydroxyaryl)pyridine derivatives bearing a carboxylate or a nitrile group suitably placed at C3 position of the aza-ring has been achieved in acceptable chemical yields with a broad functional group tolerance. This sequential C–C/C–N bond making process proceeds through a regioselective allylic alkylation/aza-Michael reaction between MBH carbonates derived from an acrylate/acrylonitrile and N-sulfonyl ketimines as C,N-binucleophiles catalyzed by DABCO, followed by elimination of SO2 under the influence of base and subsequent aromatization in an open atmosphere.

Organocatalytic Allylic Amination of Morita–Baylis–Hillman Carbonates­

An organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates with aromatic amines in the presence of β-isocupreidine is described. Chiral allylic amines were obtained in almost quantitative yields (90–96%) with moderate enantioselectivity. Recrystallization afforded products in good yields (45–73%) and high optical purity (82–99% ee). This method provides a facile and efficient route to obtain optically active β-lactams, including the building block of the cholesterol-lowering drug Ezetimibe.

Organocatalytic Enantioselective 1,3-Difunctionalizations of Morita-Baylis-Hillman Carbonates.

The in-situ-generated zwitterionic allylic ylides between Morita-Baylis-Hillman carbonates from isatins and chiral tertiary amine catalysts underwent highly regioselective and enantioselective 1,3-oxo-ethynylation or 1,3-amino-sulfenylation reactions with silyl ethynyl-1,2-benziodoxol-3( 1H)-ones or N-(aryl or alkylthio)imides, respectively, giving densely functionalized products bearing a quaternary stereogenic center. An array of diversely structured scaffolds were efficiently constructed from the products, showing the synthetic versatility of the current catalytic strategy.

Lewis-Base-Catalyzed [1 + 2 + 2] Annulation Reaction of Morita-Baylis-Hillman Carbonates with Unsaturated Pyrazolones: Construction of All-Stereogenic Carbon Cyclopentane-Fused Dispiropyrazolones.

The first Lewis-base-catalyzed unexpected [1 + 2 + 2] annulation reaction between Morita-Baylis-Hillman carbonates and unsaturated pyrazolones was developed. The multicyclic cyclopentane-fused dispiropyrazolone constructions containing five contiguous stereogenic centers, including two spiro quaternary centers, were prepared with excellent yields (81-98%) and moderate to good diastereoselectivities (1:1 to 13:1). Further transformation and gram-scale operations were also achieved efficiently.

Application of Naphthylindole-Derived Phosphines as Organocatalysts in [4 + 1] Cyclizations of o-Quinone Methides with Morita-Baylis-Hillman Carbonates.

An organocatalytic [4 + 1] cyclization of o-QMs with MBH carbonates has been established using naphthylindole-derived phosphine (NIP) as an organocatalyst. By using this approach, a series of 2,3-dihydrobenzofuran derivatives have been synthesized in high yields and excellent diastereoselectivities (up to 99% yield, >95:5 dr). This reaction not only has established the first [4 + 1] cyclization of o-QMs with MBH carbonates but also represents the first application of naphthylindole-derived phosphines as organocatalysts in catalytic reactions. In addition, this reaction has also provided a useful method for constructing 2,3-dihydrobenzofuran scaffolds.

Indolyl-chalcone derivatives induce hepatocellular carcinoma cells apoptosis through oxidative stress related mitochondrial pathway in vitro and in vivo

A facile method of assembling oxindole and phthalide units through a Lewis based catalyzed allylic alkylation reaction of Morita–Baylis–Hillman carbonates of isatins and 3-cyanophthalides was recently developed. The method efficiently delivers a hybrid of 3,3′-disubstituted oxindole with a valuable phthalide pharmacophore. In the present study, we proved the deleterious effects of 5h2c, a screened synthesis compound, against hepatocellular carcinoma (HCC) in both in vitro and in vivo models. 5h2c strongly decreased cell viability, caused over-release of lactate dehydrogenase, inhibited cell migration, and enhanced the apoptosis rate in HepG2 and PLC/PRF/5 cells. 5h2c led to an increase in intracellular reactive oxygen species levels and a decrease in mitochondrial membrane potential. In HepG2-and PLC/PRF/5-xenograft tumor mouse models, treatment with 5h2c inhibited tumor growth without affecting the animals' bodyweight or organ functions. Proteome profiling of tumor tissues after 24-h exposure to 5h2c showed significantly enhanced expression levels of Bcl-2 associated X protein, cleaved caspase −3, −8, and −9, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), heme oxygenase-2, paraoxonase 2, catalase, and factor associated suicide ligand, and reduced the expression levels of B-cell lymphoma-2, B-cell lymphoma-extra large, heat shock protein 27, heat shock protein 60, and heat shock protein 70 in HepG2 and PLC/PRF/5 cells. All of our data confirmed that oxidative stress-mediated mitochondrial apoptosis (especially the Nrf-2/HO-1 pathway) is responsible for 5h2c-induced HCC damage.

Highly efficient one-pot synthesis of fused pyrimidones from 2-heteroaryl amines and Morita–Baylis–Hillman carbonates via intermolecular cyclocondensation

A highly selective and efficient cyclocondensation reaction for construction of various 3-substituted-2H-pyrido[1,2-a]pyrimidin-2-ones and related fused pyrimidones from allylic carbonates and 2-heteroaryl amines has been developed. The transformation involves one-pot sequential aza-Michael addition, intramolecular acyl substitution, and [1,3]-H shift. The method is catalyst free, eco-friendly, scalable, and completes within a short reaction time, with no work-up, no column purification, and demonstrate a broad functional group tolerance.

Highly diastereo- and enantioselective construction of phthalide-oxindole hybrids bearing vicinal quaternary chiral centers via an organocatalytic allylic alkylation

A diastereo- and enantioselective synthesis of phthalide-oxindole hybrids including congested adjacent quaternary chiral centers was demonstrated through a Lewis base catalyzed asymmetric allylic alkylation reaction of Morita–Baylis–Hillman carbonates of isatins and 3-cyanophthalides. The various hybrid molecules with two valuable pharmacophores-combined frameworks can be obtained in good to high diastereo- and enantioselectivities.

Phosphine-Catalyzed Enantioselective [4 + 2] Cycloaddition–Semipinacol-Type-Rearrangement Reaction of Morita–Baylis–Hillman Carbonates

The chiral phosphine-triggered electrophilic ylide intermediate for a Morita-Baylis-Hillman carbonates activation strategy provides a promising method for the design of organocatalytic intermolecular higher-order annulation processes.

Lewis‐Base‐Catalyzed Domino Reaction of Morita–Baylis–Hillman Carbonates of Isatins with Enolizable Cyclic Carbonyl Compounds: Stereoselective Access to Spirooxindole‐Pyrans

AbstractThe present paper reports an efficient, organocatalytic, environmentally friendly and stereoselective [3+3] one‐pot allylic alkylation/oxa‐Michael reaction by involving a wide range of Morita–Baylis–Hillman (MBH) carbonates of isatins and several pharmacologically attractive enolizable C−H activated cyclic carbonyl compounds such as 1,3‐binucleophiles, namely pyrazolones, isoxazolones, 4‐hydroxyxoumarins, 4‐hydroxy‐6‐methyl‐α‐pyrone, lawsone and dimedone in a biomass‐derived 2‐MeTHF as green solvent catalyzed by DABCO as a solid Lewis‐base catalyst. This protocol delivers a unique class of medicinally promising spirooxindole‐fused‐dihydropyran scaffolds.

Stereoselective Synthesis of 3,3-Disubstituted Oxindoles and Spirooxindoles via Allylic Alkylation of Morita-Baylis-Hillman Carbonates of Isatins with Cyclic Sulfamidate Imines Catalyzed by DABCO.

An efficient, organocatalytic, and ecofriendly method has been developed for the quick construction of a wide array of 3,3-disubstituted oxindoles in good to excellent yields and diastereomeric ratio (up to ≤96:4) with excellent functional group tolerance via an allylic alkylation reaction of cyclic sulfamidate imines with a number of MBH carbonates of isatins in 2-MeTHF as an environmentally benign solvent at room temperature using 5 mol % of DABCO. Furthermore, a metal-free-based one-shot synthesis of a medicinally promising polycyclic spirooxindole with an all-carbon spirocenter has been achieved with outstanding dr value (up to ≤99:1).

Enantioselective Synthesis of Carbocyclic Nucleosides via Asymmetric [3 + 2] Annulation of α-Purine-Substituted Acrylates with MBH Carbonates.

An efficient route to chiral carbocyclic nucleoside analogues containing a quaternary stereocenter and a C═C double bond has been established via a highly enantioselective [3 + 2] annulation of Morita-Baylis-Hillman (MBH) carbonates with α-purine-substituted acrylates. With 20 mol % (S)-SITCP as the catalyst, various chiral carbocyclic nucleoside analogues with a quaternary stereocenter and a C═C double bond were obtained in high yields (up to 92%) with good diastereoselectivities (up to 10:1 dr) and excellent enantioselectivities (up to 96% ee). Furthermore, the corresponding products were subjected to diverse transformations to afford interesting and potentially useful chiral carbocyclic nucleosides.