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15 pages, 4294 KiB

Open AccessArticle

Synthesis and Reactivity of Oligo(ethylene glycol)-Tethered Morita–Baylis–Hillman Dimers in the Formation of Macrocyclic Structures Showing Remarkable Cytotoxicity

by Marco Paolino, Mario Saletti, Jacopo Venditti, Arianna Zacchei, Alessandro Donati, Claudia Bonechi, Germano Giuliani, Stefania Lamponi and Andrea Cappelli

Pharmaceuticals 2025, 18(4), 473; https://doi.org/10.3390/ph18040473 - 27 Mar 2025

Viewed by 317

Abstract

Background/Objectives: Crown ethers have received increasing interest owing to their ability to form stable complexes with cations. This molecular feature has been successfully exploited in the development of biologically relevant ionophores. Methods: In order to obtain innovative crown ethers derivatives, a [...] Read more.

Background/Objectives: Crown ethers have received increasing interest owing to their ability to form stable complexes with cations. This molecular feature has been successfully exploited in the development of biologically relevant ionophores. Methods: In order to obtain innovative crown ethers derivatives, a Morita–Baylis–Hillman adduct (MBHA) acetate (4) bearing a phenylacetylene moiety was dimerized via the click-chemistry CuAAC reaction with oligo(ethylene glycol) diazide derivatives to build-up a small series of dimeric MBHA derivatives (5a-d). These dimeric MBHA derivatives were reacted with n-butylamine to afford tunable macrocyclic crown ether-paracyclophane hybrid architectures (6a-d). Results: Compounds (E,Z)-6a, (E,E)-6a, 6b-d showed, in human breast cancer MDA-MB-231 and human melanoma A375 cells, IC₅₀ values comparable with those of reference anticancer agent Doxorubicin. Conclusions: This exploration approach provides original new macrocyclic architectures potentially useful as anticancer agents. Full article

(This article belongs to the Section Medicinal Chemistry)

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19 pages, 8488 KiB

Open AccessArticle

DABCO/Amberlyst^® 15-Cocatalysed One-Pot Three-Component Aza-Morita–Baylis–Hillman Reaction Under Green Conditions

by Giovanna Bosica, Riccardo De Nittis and Matthew Vella Refalo

Catalysts 2024, 14(12), 873; https://doi.org/10.3390/catal14120873 - 29 Nov 2024

Viewed by 1003

Abstract

The one-pot multicomponent aza-Morita–Baylis–Hillman (MBH) reaction was performed under green conditions using 1,4-diazabicyclo[2.2.2]octane (DABCO) and Amberlyst^® 15 as a co-catalyst, at ambient temperature and under negligible amounts of non-hazardous solvent. A number of α-methylene-β-amino acid derivatives were produced in good to excellent [...] Read more.

The one-pot multicomponent aza-Morita–Baylis–Hillman (MBH) reaction was performed under green conditions using 1,4-diazabicyclo[2.2.2]octane (DABCO) and Amberlyst^® 15 as a co-catalyst, at ambient temperature and under negligible amounts of non-hazardous solvent. A number of α-methylene-β-amino acid derivatives were produced in good to excellent yields from different arylaldehydes, p-toluenesulfonamide and α,β-unsaturated carbonyl compounds. The environmental benignity of the process is accounted by the low E-factor (0.7) and high atom economy (95%) values obtained. Full article

(This article belongs to the Section Catalytic Materials)

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30 pages, 6125 KiB

Open AccessReview

Advances in Chiral Pincer Complexes: Insights and Applications in Catalytic Asymmetric Reactions

by Sanaa Musa, Yuval Peretz and Gil Dinnar

Int. J. Mol. Sci. 2024, 25(19), 10344; https://doi.org/10.3390/ijms251910344 - 26 Sep 2024

Cited by 1 | Viewed by 1979

Abstract

Chiral pincer complexes, characterized by their rigid tridentate coordination framework, have emerged as powerful catalysts in asymmetric synthesis. This review provides a comprehensive overview of recent advancements in the development of chiral pincer-type ligands and their corresponding transition metal complexes. We highlight the [...] Read more.

Chiral pincer complexes, characterized by their rigid tridentate coordination framework, have emerged as powerful catalysts in asymmetric synthesis. This review provides a comprehensive overview of recent advancements in the development of chiral pincer-type ligands and their corresponding transition metal complexes. We highlight the latest progress in their application across a range of catalytic asymmetric reactions, including the (transfer) hydrogenation of polar and non-polar bonds, hydrophosphination, alkynylation, Friedel-Crafts reactions, enantioselective reductive cyclization of alkynyl-tethered cyclohexadienones, enantioselective hydrosilylation, as well as Aza–Morita–Baylis–Hillman reactions. The structural rigidity and tunability of chiral pincer complexes enable precise control over stereoselectivity, resulting in high enantioselectivity and efficiency in complex molecular transformations. As the field advances, innovations in ligand design and the exploration of new metal centers are expected to expand the scope and utility of these catalysts, bearing significant implications for the synthesis of enantioenriched compounds in pharmaceuticals, materials science, and beyond. Full article

(This article belongs to the Special Issue Coordination Complexes: From Molecular Design to Functional Applications)

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23 pages, 7944 KiB

Open AccessArticle

Novel 1,2,4-Triazole- and Tetrazole-Containing 4H-Thiopyrano[2,3-b]quinolines: Synthesis Based on the Thio-Michael/aza-Morita–Baylis–Hillman Tandem Reaction and Investigation of Antiviral Activity

by Andrey V. Khramchikhin, Mariya A. Skryl’nikova, Maxim A. Gureev, Vladimir V. Zarubaev, Iana L. Esaulkova, Polina A. Ilyina, Oussama Abdelhamid Mammeri, Dar’ya V. Spiridonova, Yuri B. Porozov and Vladimir A. Ostrovskii

Molecules 2023, 28(21), 7427; https://doi.org/10.3390/molecules28217427 - 4 Nov 2023

Cited by 3 | Viewed by 1744

Abstract

A novel method for synthesizing 1,2,4-triazole- and tetrazole-containing 4H-thiopyrano[2,3-b]quinolines using a new combination of the thio-Michael and aza-Morita–Baylis–Hillman reactions was developed. Target compounds were evaluated for their cytotoxicities and antiviral activities against influenza A/Puerto Rico/8/34 virus in MDCK cells. [...] Read more.

A novel method for synthesizing 1,2,4-triazole- and tetrazole-containing 4H-thiopyrano[2,3-b]quinolines using a new combination of the thio-Michael and aza-Morita–Baylis–Hillman reactions was developed. Target compounds were evaluated for their cytotoxicities and antiviral activities against influenza A/Puerto Rico/8/34 virus in MDCK cells. The compounds showed low toxicity and some exhibited moderate antiviral activity. Molecular docking identified the M2 channel and polymerase basic protein 2 as potential targets. We observed that the antiviral activity of thiopyrano[2,3-b]quinolines is notably affected by both the nature and position of the substituent within the tetrazole ring, as well as the substituent within the benzene moiety of quinoline. These findings contribute to the further search for new antiviral agents against influenza A viruses among derivatives of thiopyrano[2,3-b]quinoline. Full article

(This article belongs to the Special Issue Triazoles and Tetrazoles: Current Status and Perspective)

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17 pages, 1474 KiB

Open AccessArticle

Substrate-Controlled Diversity-Oriented Synthesis of Novel Polycyclic Frameworks via [4 + 2] and [3 + 2] Annulations of Ninhydrin-Derived MBH Adducts with 3,4-Dihydroisoquinolines

by Kaikai Wang, Wenwen Zhou, Jun Jia, Junwei Ye, Mengxin Yuan, Jie Yang, Yonghua Qi and Rongxiang Chen

Molecules 2023, 28(19), 6761; https://doi.org/10.3390/molecules28196761 - 22 Sep 2023

Cited by 6 | Viewed by 1567

Abstract

Substrate-controlled diversity-oriented synthesis of polycyclic frameworks via [4 + 2] and [3 + 2] annulations between ninhydrin-derived Morita–Baylis–Hillman (MBH) adducts and 3,4-dihydroisoquinolines under similar reaction conditions have been developed. The reaction provides diversity-oriented synthesis of a series of novel and structurally complex spiro [...] Read more.

Substrate-controlled diversity-oriented synthesis of polycyclic frameworks via [4 + 2] and [3 + 2] annulations between ninhydrin-derived Morita–Baylis–Hillman (MBH) adducts and 3,4-dihydroisoquinolines under similar reaction conditions have been developed. The reaction provides diversity-oriented synthesis of a series of novel and structurally complex spiro multi heterocyclic skeletons in good yields (up to 87% and 90%, respectively) with excellent diastereoselectivities (up to >25:1 dr). In particular, the switchable [4 + 2] and [3 + 2] annulation reactions are controlled by tuning the hydroxyl protecting group on the ninhydrin-derived MBH adduct to deliver structural diverse spiro[indene-2,2′-[1,3]oxazino[2,3-a]isoquinoline] and spiro[indene-2,1′-pyrrolo[2,1-a]isoquinoline], respectively. Furthermore, the relative configuration and chemical structure of two kinds of cycloadducts were confirmed through X-ray diffraction analysis. Full article

(This article belongs to the Section Organic Chemistry)

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11 pages, 2370 KiB

Open AccessArticle

Application of Chitosan/Poly(vinyl alcohol) Stabilized Copper Film Materials for the Borylation of α, β-Unsaturated Ketones, Morita-Baylis-Hillman Alcohols and Esters in Aqueous Phase

by Bojie Li, Wu Wen, Wei Wen, Haifeng Guo, Chengpeng Fu, Yaoyao Zhang and Lei Zhu

Molecules 2023, 28(14), 5609; https://doi.org/10.3390/molecules28145609 - 24 Jul 2023

Cited by 2 | Viewed by 1640

Abstract

A chitosan/poly(vinyl alcohol)-stabilized copper nanoparticle (CP@Cu NPs) was used as a heterogeneous catalyst for the borylation of α, β-unsaturated ketones, MBH alcohols, and MBH esters in mild conditions. This catalyst not only demonstrated remarkable efficiency in synthesizing organoboron compounds but also still maintained [...] Read more.

A chitosan/poly(vinyl alcohol)-stabilized copper nanoparticle (CP@Cu NPs) was used as a heterogeneous catalyst for the borylation of α, β-unsaturated ketones, MBH alcohols, and MBH esters in mild conditions. This catalyst not only demonstrated remarkable efficiency in synthesizing organoboron compounds but also still maintained excellent reactivity and stability even after seven recycled uses of the catalyst. This methodology provides a gentle and efficient approach to synthesize the organoboron compounds by efficiently constructing carbon–boron bonds. Full article

(This article belongs to the Special Issue Catalysis for Green Chemistry)

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14 pages, 3286 KiB

Open AccessArticle

Synthesis and Elimination Pathways of 1-Methanesulfonyl-1,2-dihydroquinoline Sulfonamides

by Ebenezer Ametsetor, Kwabena Fobi and Richard A. Bunce

Molecules 2023, 28(7), 3256; https://doi.org/10.3390/molecules28073256 - 5 Apr 2023

Cited by 1 | Viewed by 2350

Abstract

A series of new Morita–Baylis–Hillman acetates were prepared and reacted with methanesulfonamide (K₂CO₃, DMF, 23 °C) to produce tertiary dihydroquinoline sulfonamides in high yields. Subsequent efforts to eliminate the methylsulfonyl group from these derivatives (K₂CO₃, [...] Read more.

A series of new Morita–Baylis–Hillman acetates were prepared and reacted with methanesulfonamide (K₂CO₃, DMF, 23 °C) to produce tertiary dihydroquinoline sulfonamides in high yields. Subsequent efforts to eliminate the methylsulfonyl group from these derivatives (K₂CO₃, DMF, 90 °C) as a route to quinolines were met with mixed results. Although dihydroquinoline sulfonamides prepared from ethyl acrylate and acrylonitrile generally underwent elimination to give excellent yields of quinolines, those generated from 3-buten-2-one failed to undergo elimination and instead decomposed. The failure of these ketone substrates to aromatize presumably derives from the enolizable methyl ketone at C-3. Finally, the attempted aromatization of the acrylate-derived 6,7-difluoro-1,2-dihydroquinoline sulfonamide demonstrated that other interesting processes could occur in preference to the desired elimination. Full article

(This article belongs to the Special Issue Molecules in 2023)

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15 pages, 2690 KiB

Open AccessArticle

DABCO-Catalyzed Mono-/Diallylation of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Morita-Baylis-Hillman Carbonates

by Qiumi Wang, Sicheng Li, Guosheng Yang, Xinyu Zou, Xi Yin, Juhua Feng, Huabao Chen, Chunping Yang, Li Zhang, Cuifen Lu and Guizhou Yue

Molecules 2023, 28(7), 3002; https://doi.org/10.3390/molecules28073002 - 28 Mar 2023

Cited by 5 | Viewed by 2215

Abstract

Allylation of N-unsubstituted isatin N,N′-cyclic azomethine imines with Morita-Baylis-Hillman carbonates in the presence of 1–10 mol% DABCO in DCM at room temperature, rapidly gave N-allylated and N, β-diallylated isatin N,N′-cyclic azomethine imine 1,3-dipoles [...] Read more.

Allylation of N-unsubstituted isatin N,N′-cyclic azomethine imines with Morita-Baylis-Hillman carbonates in the presence of 1–10 mol% DABCO in DCM at room temperature, rapidly gave N-allylated and N, β-diallylated isatin N,N′-cyclic azomethine imine 1,3-dipoles in moderate to high yields. The reaction features mild reaction conditions, easily practical operation, and short reaction times in most cases. Furthermore, the alkylated products were transformed into novel bicyclic spiropyrrolidine oxoindole derivatives through the [3+2] or [3+3]-cycloaddition with maleimides or Knoevenagel adducts. Full article

(This article belongs to the Special Issue Chemistry of Nitrogen Heterocyclic Compounds)

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10 pages, 1329 KiB

Open AccessCommunication

Chiral Phosphine Catalyzed Allylic Alkylation of Benzylidene Succinimides with Morita–Baylis–Hillman Carbonates

by Chang Liu, Jianwei Sun and Pengfei Li

Molecules 2023, 28(6), 2825; https://doi.org/10.3390/molecules28062825 - 21 Mar 2023

Cited by 4 | Viewed by 2189

Abstract

Owing to their unique chemical properties, α-alkylidene succinimides generally act as versatile synthons in organic synthesis. Compared with well-established annulations, nucleophilic alkylations of α-alkylidene succinimides are very limited. Accordingly, an organocatalytic allylic alkylation of α-benzylidene succinimides with Morita–Baylis–Hillman (MBH) carbonates was established. In [...] Read more.

Owing to their unique chemical properties, α-alkylidene succinimides generally act as versatile synthons in organic synthesis. Compared with well-established annulations, nucleophilic alkylations of α-alkylidene succinimides are very limited. Accordingly, an organocatalytic allylic alkylation of α-benzylidene succinimides with Morita–Baylis–Hillman (MBH) carbonates was established. In the presence of a chiral phosphine catalyst, α-benzylidene succinimides reacted smoothly with MBH carbonates under mild conditions to furnish a series of optical active succinimides in high yields and enantioselectivities. Different from the reported results, the organocatalytic enantioselective construction of pyrrolidine-2,5-dione frameworks bearing contiguous chiral tertiary carbon centers was achieved via this synthetic strategy. Scaling up the reaction indicated that it is a practical strategy for the organocatalytic enantioselective alkylation of α-alkylidene succinimides. A possible reaction mechanism was also proposed. Full article

(This article belongs to the Special Issue Recent Advances of Catalytic Asymmetric Synthesis)

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23 pages, 37037 KiB

Open AccessArticle

A New MBH Adduct as an Efficient Ligand in the Synthesis of Metallodrugs: Characterization, Geometrical Optimization, XRD, Biological Activities, and Molecular Docking Studies

by Shazia Ishfaq, Shazia Nisar, Sadaf Iqbal, Saqib Ali, Syed Tariq Ali, ElSayed Din, Norah Salem Alsaiari, Kholood A. Dahlous, Muhammad Sufyan Javed and Patrizia Bocchetta

Molecules 2022, 27(23), 8150; https://doi.org/10.3390/molecules27238150 - 23 Nov 2022

Cited by 1 | Viewed by 2426

Abstract

This article reports the synthesis, characterization, geometrical optimization, and biological studies of new MBH-based organometallic compounds of medicinal significance. The ligand (MNHA) was prepared via the Morita–Baylis–Hillman (MBH) synthetic route, from aromatic aldehyde containing multiple functional groups. Metal complexes were prepared in an [...] Read more.

This article reports the synthesis, characterization, geometrical optimization, and biological studies of new MBH-based organometallic compounds of medicinal significance. The ligand (MNHA) was prepared via the Morita–Baylis–Hillman (MBH) synthetic route, from aromatic aldehyde containing multiple functional groups. Metal complexes were prepared in an alkaline medium and under other suitable reaction conditions. Spectral and elemental analyses were used to identify the structural and molecular formulas of each compound. Optimized geometry was determined through density functional theory (DFT) B3LYP and 6-311++ G (d,p) basis set for the MBH adduct, whereas structures of novel complexes were optimized with the semi-empirical PM6 method. Powder XRD analysis furnished the crystal class of complexes, with Co³⁺, Cr³⁺, and Mn²⁺ being cubic, while Ni²⁺ was hexagonal, and Cu²⁺ was orthorhombic. Moreover, the ligand, along with Ni²⁺ and Co³⁺ complexes, showed profound antibacterial action against S. aureus, E. coli, B. pumilis, and S. typhi. Additionally, all of the complexes were shown to persist in the positive antioxidant potential of the ligand. Contrarily, not a single metal complex conserved the antifungal potentials of the ligand. Full article

(This article belongs to the Special Issue Novel Aspects in Nanomaterials for Biomedical and Environmental Applications)

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24 pages, 5088 KiB

Open AccessArticle

Synthesis and Characterization with Computational Studies of Metal Complexes of Methyl 2-((4-cyanophenyl)(hydroxy) methyl)acrylate: A New Biologically Active Multi-Functional Adduct

by Shazia Ishfaq, Shazia Nisar, Amtul Qayum, Sadaf Iqbal, Nasreen Fatima, Fatmah Ali Alasmary, Amani Salem Almalki, ElSayed M. Tag El Din, Muhammad Sufyan Javed and Patrizia Bocchetta

Separations 2022, 9(10), 306; https://doi.org/10.3390/separations9100306 - 13 Oct 2022

Viewed by 3327

Abstract

The title ligand (L^”_x), methyl 2-((4-cyanophenyl)(hydroxy)methyl)acrylate was synthesized following the Morita-Baylis-Hillman reaction scheme. Spectroscopic techniques such as: UV- Visible, FT-IR, ESI-MS, and ¹H NMR helped in characterization of the L^”_x. Complexes of Cr³⁺, Co [...] Read more.

The title ligand (L^”_x), methyl 2-((4-cyanophenyl)(hydroxy)methyl)acrylate was synthesized following the Morita-Baylis-Hillman reaction scheme. Spectroscopic techniques such as: UV- Visible, FT-IR, ESI-MS, and ¹H NMR helped in characterization of the L^”_x. Complexes of Cr³⁺, Co³⁺, Ni²⁺, Mn²⁺, Cu²⁺ with L^”_x were prepared and characterized by UV- Visible, FT-IR and powder-XRD. FTIR spectrum of the L^”_x generated through DFT B3LYP method and 6-311++ G (d,p) basis set was found in good agreement with experimental spectrum. Additionally, the semi-empirical PM6 method optimization helped propose the most suitable geometries of the complexes with Cr³⁺, Co³⁺ possessing octahedral, Ni²⁺ square planner, Mn²⁺ and Cu²⁺ tetrahedral geometries. Powder-XRD patterns of the complexes have revealed cubic crystal class for Cr³⁺ and Co³⁺, whereas hexagonal, orthorhombic, and monoclinic for Ni²⁺, Mn^2+, and Cu²⁺ complexes were observed, respectively. In addition, the nano-particle size was found in the range of 8.2560–4.5316 nm for complexes. Antibacterial activity against S. aureus, E. coli, B. pumilis and S. typhi confirmed a substantially high potential, as endorsed by their Molecular docking studies, of Ni²⁺ and Cu²⁺ complexes against each bacterial strain. Moreover, all compounds exhibited positive antioxidant activities, but have no antifungal potential except L^”_x. The current study demonstrates the usefulness of these novel transition metal complexes as possible potent antibacterial and antioxidant agents. Full article

(This article belongs to the Topic Discovery of Bioactive Compounds from Natural Organisms and Their Molecular Mechanisms against Diseases)

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52 pages, 14174 KiB

Open AccessReview

Microbial Lipases and Their Potential in the Production of Pharmaceutical Building Blocks

by César A. Godoy, Juan S. Pardo-Tamayo and Oveimar Barbosa

Int. J. Mol. Sci. 2022, 23(17), 9933; https://doi.org/10.3390/ijms23179933 - 1 Sep 2022

Cited by 39 | Viewed by 5773

Abstract

Processes involving lipases in obtaining active pharmaceutical ingredients (APIs) are crucial to increase the sustainability of the industry. Despite their lower production cost, microbial lipases are striking for their versatile catalyzing reactions beyond their physiological role. In the context of taking advantage of [...] Read more.

Processes involving lipases in obtaining active pharmaceutical ingredients (APIs) are crucial to increase the sustainability of the industry. Despite their lower production cost, microbial lipases are striking for their versatile catalyzing reactions beyond their physiological role. In the context of taking advantage of microbial lipases in reactions for the synthesis of API building blocks, this review focuses on: (i) the structural origins of the catalytic properties of microbial lipases, including the results of techniques such as single particle monitoring (SPT) and the description of its selectivity beyond the Kazlauskas rule as the “Mirror-Image Packing” or the “Key Region(s) rule influencing enantioselectivity” (KRIE); (ii) immobilization methods given the conferred operative advantages in industrial applications and their modulating capacity of lipase properties; and (iii) a comprehensive description of microbial lipases use as a conventional or promiscuous catalyst in key reactions in the organic synthesis (Knoevenagel condensation, Morita–Baylis–Hillman (MBH) reactions, Markovnikov additions, Baeyer–Villiger oxidation, racemization, among others). Finally, this review will also focus on a research perspective necessary to increase microbial lipases application development towards a greener industry. Full article

(This article belongs to the Special Issue Biocatalysis: An Eco-Friendly Scenario for the Manufacturing of APIs)

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8 pages, 1181 KiB

Open AccessArticle

Highly Efficient Asymmetric Morita–Baylis–Hillman Reaction Promoted by Chiral Aziridine-Phosphines

by Aleksandra Buchcic-Szychowska, Anna Zawisza, Stanisław Leśniak and Michał Rachwalski

Catalysts 2022, 12(4), 394; https://doi.org/10.3390/catal12040394 - 31 Mar 2022

Cited by 8 | Viewed by 2638

Abstract

Continuing our research on the use of organophosphorus derivatives of aziridines in asymmetric synthesis and expanding the scope of their applicability, chiral aziridine-phosphines obtained earlier in our laboratory were used as chiral catalysts in the asymmetric Morita–Baylis–Hillman reaction of methyl vinyl ketone and [...] Read more.

Continuing our research on the use of organophosphorus derivatives of aziridines in asymmetric synthesis and expanding the scope of their applicability, chiral aziridine-phosphines obtained earlier in our laboratory were used as chiral catalysts in the asymmetric Morita–Baylis–Hillman reaction of methyl vinyl ketone and methyl acrylate with various aromatic aldehydes. The desired chiral products were formed in moderate to high chemical yields and with enantiomeric excess reaching value of 98% ee in some cases. The use of catalysts being pairs of enantiomers led to the desired products with opposite absolute configurations. Full article

(This article belongs to the Special Issue Advances in Asymmetric Organocatalytic Reactions)

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14 pages, 3051 KiB

Open AccessArticle

Kinetic Resolution in Transannular Morita-Baylis-Hillman Reaction: An Approximation to the Synthesis of Sesquiterpenes from Guaiane Family

by Raquel Mato, Rubén Manzano, Efraím Reyes, Liher Prieto, Uxue Uria, Luisa Carrillo and Jose L. Vicario

Catalysts 2022, 12(1), 67; https://doi.org/10.3390/catal12010067 - 8 Jan 2022

Cited by 3 | Viewed by 2606

Abstract

An approximation to the synthesis of several sesquiterpenes from the Guaiane family is described in which the core structure was obtained through a transannular Morita-Baylis-Hillman reaction performed under kinetic resolution. Several manipulations of the obtained MBH adduct have been carried out directed towards [...] Read more.

An approximation to the synthesis of several sesquiterpenes from the Guaiane family is described in which the core structure was obtained through a transannular Morita-Baylis-Hillman reaction performed under kinetic resolution. Several manipulations of the obtained MBH adduct have been carried out directed towards the total synthesis of γ-Gurjunene, to the formal synthesis of Clavukerin A, to the synthesis of a non-natural isomer of isoguaiane and to the synthesis of an advanced intermediate in the total synthesis of Palustrol. Full article

(This article belongs to the Special Issue Organocatalysis: Mechanistic Investigations, Design, and Applications)

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47 pages, 24623 KiB

Open AccessReview

Asymmetric Catalytic Ketimine Mannich Reactions and Related Transformations

by Changgong Xu, Carlyn Reep, Jamielyn Jarvis, Brandon Naumann, Burjor Captain and Norito Takenaka

Catalysts 2021, 11(6), 712; https://doi.org/10.3390/catal11060712 - 7 Jun 2021

Cited by 17 | Viewed by 6389

Abstract

The catalytic enantioselective ketimine Mannich and its related reactions provide direct access to chiral building blocks bearing an α-tertiary amine stereogenic center, a ubiquitous structural motif in nature. Although ketimines are often viewed as challenging electrophiles, various approaches/strategies to circumvent or overcome the [...] Read more.

The catalytic enantioselective ketimine Mannich and its related reactions provide direct access to chiral building blocks bearing an α-tertiary amine stereogenic center, a ubiquitous structural motif in nature. Although ketimines are often viewed as challenging electrophiles, various approaches/strategies to circumvent or overcome the adverse properties of ketimines have been developed for these transformations. This review showcases the selected examples that highlight the benefits and utilities of various ketimines and remaining challenges associated with them in the context of Mannich, allylation, and aza-Morita–Baylis–Hillman reactions as well as their variants. Full article

(This article belongs to the Special Issue Catalytic Organic Transformations/Organic Synthesis)

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