Research

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8 pages, 1929 KiB

Open AccessArticle

Design and Synthesis of a Novel Banana-Shaped Functional Molecule via Double Cross-Coupling

by Bingchuan Yang, Guodong Shen, Xianqiang Huang and Rutao Liu

Molecules 2019, 24(4), 698; https://doi.org/10.3390/molecules24040698 - 15 Feb 2019

Cited by 4 | Viewed by 3392

A novel banana-shaped molecule using 2,8-Dimethyl-6H,12H-5,11-methanodibenzo [b,f] [1,5]diazocine (Tröger’s base) as bent-core was synthesized via double Carbon-Carbon cross-coupling reaction. The double Sonogashira cross-coupling reaction was optimized by using Pd(PPh₃)₂Cl₂ as catalyst, CuI [...] Read more.

A novel banana-shaped molecule using 2,8-Dimethyl-6H,12H-5,11-methanodibenzo [b,f] [1,5]diazocine (Tröger’s base) as bent-core was synthesized via double Carbon-Carbon cross-coupling reaction. The double Sonogashira cross-coupling reaction was optimized by using Pd(PPh₃)₂Cl₂ as catalyst, CuI as cocatalyst and diisopropylamine as base in place of triethylamine. The structure of this compound was confirmed by ¹H-NMR, ¹³C-NMR, Fourier transform infrared (FT-IR) spectroscopy and mass spectrometry. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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13 pages, 1630 KiB

Open AccessArticle

Synthesis of Pyridazine Derivatives by Suzuki-Miyaura Cross-Coupling Reaction and Evaluation of Their Optical and Electronic Properties through Experimental and Theoretical Studies

by Sara S. M. Fernandes, João Aires-de-Sousa, Michael Belsley and M. Manuela M. Raposo

Molecules 2018, 23(11), 3014; https://doi.org/10.3390/molecules23113014 - 18 Nov 2018

Cited by 7 | Viewed by 4249

Abstract

A series of π-conjugated molecules, based on pyridazine and thiophene heterocycles 3a–e, were synthesized using commercially, or readily available, coupling components, through a palladium catalyzed Suzuki-Miyaura cross-coupling reaction. The electron-deficient pyridazine heterocycle was functionalized by a thiophene electron-rich heterocycle at [...] Read more.

A series of π-conjugated molecules, based on pyridazine and thiophene heterocycles 3a–e, were synthesized using commercially, or readily available, coupling components, through a palladium catalyzed Suzuki-Miyaura cross-coupling reaction. The electron-deficient pyridazine heterocycle was functionalized by a thiophene electron-rich heterocycle at position six, and different (hetero)aromatic moieties (phenyl, thienyl, furanyl) were functionalized with electron acceptor groups at position three. Density Functional Theory (DFT) calculations were carried out to obtain information on the conformation, electronic structure, electron distribution, dipolar moment, and molecular nonlinear response of the synthesized push-pull pyridazine derivatives. Hyper-Rayleigh scattering in 1,4-dioxane solutions, using a fundamental wavelength of 1064 nm, was used to evaluate their second-order nonlinear optical properties. The thienylpyridazine functionalized with the cyano-phenyl moiety exhibited the largest first hyperpolarizability (β = 175 × 10⁻³⁰ esu, using the T convention) indicating its potential as a second harmonic generation (SHG) chromophore. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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14 pages, 4504 KiB

Open AccessArticle

Zinc (II)-Mediated Selective O-Benzylation of 2-Oxo-1,2-Dihydropyridines Systems

by Qifan Zhou, Fangyu Du, Xinjie Liang, Wenqiang Liu, Ting Fang and Guoliang Chen

Molecules 2018, 23(7), 1784; https://doi.org/10.3390/molecules23071784 - 20 Jul 2018

Cited by 5 | Viewed by 4359

Abstract

The selective O-benzylation of 2-oxo-1,2-dihydropyridines plays a critical role in organic synthesis of natural products and biological active molecules. Herein we report a novel ternary system of ZnO, ZnCl₂ and N,N-diisopropylethylamine (DIEA), that is highly effective for selective [...] Read more.

The selective O-benzylation of 2-oxo-1,2-dihydropyridines plays a critical role in organic synthesis of natural products and biological active molecules. Herein we report a novel ternary system of ZnO, ZnCl₂ and N,N-diisopropylethylamine (DIEA), that is highly effective for selective O-benzylation of 2-oxo-1,2-dihydropyridines using abundant substituted benzyl halides and related substituted 2-oxo-1,2-dihydropyridines compounds. This process allows access to a variety of O-benzyl products under mild reaction conditions, which are important synthetic intermediates in the protection of functional groups, and represents a new method toward the development for the O-benzylation of 2-oxo-1,2-dihydropyridines. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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Review

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60 pages, 19705 KiB

Open AccessReview

Synthesis of Phthalides and α,β-butenolides by Transition Metal-Catalyzed Activation of C—H Bonds

by Andrea Renzetti and Kozo Fukumoto

Molecules 2019, 24(4), 824; https://doi.org/10.3390/molecules24040824 - 25 Feb 2019

Cited by 20 | Viewed by 7639

Abstract

Phthalides and α,β-butenolides are two related classes of oxygenated heterocycles with a wide range of biological activities. An innovative strategy to prepare these compounds is based on C—H bond functionalization reactions, in which two simple, unfunctionalized molecules are coupled together with cleavage of [...] Read more.

Phthalides and α,β-butenolides are two related classes of oxygenated heterocycles with a wide range of biological activities. An innovative strategy to prepare these compounds is based on C—H bond functionalization reactions, in which two simple, unfunctionalized molecules are coupled together with cleavage of a C—H bond and formation of a C—X bond (X=C or heteroatom). This paper reviews the methods for the synthesis of phthalides and α,β-butenolides by C—H bond functionalization from non-halogenated starting materials. Over 30 methods are reported, mostly developed during the past ten years. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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74 pages, 24536 KiB

Open AccessFeature PaperReview

Palladium-Catalysed Synthesis and Transformation of Quinolones

by Vera L. M. Silva and Artur M. S. Silva

Molecules 2019, 24(2), 228; https://doi.org/10.3390/molecules24020228 - 09 Jan 2019

Cited by 24 | Viewed by 6462

Abstract

Palladium-catalysed reactions have had a large impact on synthetic organic chemistry and have found many applications in target-oriented synthesis. Their widespread use in organic synthesis is due to the mild conditions associated with the reactions together with their tolerance of a wide range [...] Read more.

Palladium-catalysed reactions have had a large impact on synthetic organic chemistry and have found many applications in target-oriented synthesis. Their widespread use in organic synthesis is due to the mild conditions associated with the reactions together with their tolerance of a wide range of functional groups. Moreover, these types of reactions allow the rapid construction of complex molecules through multiple bond-forming reactions in a single step, the so-called tandem processes. Pd-catalysed reactions have been applied to the synthesis of a large number of natural products and bioactive compounds, some of them of complex molecular structures. This review article aims to present an overview of the most important Pd-catalysed reactions employed in the synthesis and transformations of quinolin-2(1H)-ones and quinolin-4(1H)-ones. These compounds are widely recognized by their diverse bioactivity, being privileged structures in medicinal chemistry and useful structural moieties for the development of new drug candidates. Furthermore, they hold significant interest due to their host–guest chemistry; applications in chemical, biochemical and environmental analyses and use in the development of new synthetic methods. In some cases, the quinolone formation step cannot be ascribed to a claimed Pd-catalysed reaction but this reaction is crucial to get the appropriate substrate for cyclization into the quinolone. Herein we present and discuss different economical, efficient and selective synthetic strategies to access quinolone-type compounds. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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16 pages, 3980 KiB

Open AccessReview

Metal-Catalyzed Cross-Coupling Reactions on Azaindole Synthesis and Functionalization

by A. Sofia Santos, Ana C. Mortinho and M. Manuel B. Marques

Molecules 2018, 23(10), 2673; https://doi.org/10.3390/molecules23102673 - 17 Oct 2018

Cited by 29 | Viewed by 4844

Abstract

Azaindoles are rare in nature but extremely attractive for drug discovery programs. Azaindoles can be obtained by diverse methods, including those involving metal-catalyzed reactions. This important core has been fascinating the scientific community due to their challenging synthesis and relevant bioactivity. This paper [...] Read more.

Azaindoles are rare in nature but extremely attractive for drug discovery programs. Azaindoles can be obtained by diverse methods, including those involving metal-catalyzed reactions. This important core has been fascinating the scientific community due to their challenging synthesis and relevant bioactivity. This paper highlights the diverse synthetic methodologies developed to date involving metal-catalyzed reaction to attain azaindoles and its functionalization. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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24 pages, 5830 KiB

Open AccessReview

The Current Status of Heterogeneous Palladium Catalysed Heck and Suzuki Cross-Coupling Reactions

by Philani P. Mpungose, Zanele P. Vundla, Glenn E. M. Maguire and Holger B. Friedrich

Molecules 2018, 23(7), 1676; https://doi.org/10.3390/molecules23071676 - 10 Jul 2018

Cited by 118 | Viewed by 9091

Abstract

In the last 30 years, C–C cross coupling reactions have become a reliable technique in organic synthesis due their versatility and efficiency. While drawbacks have been experienced on an industrial scale with the use of homogenous systems, many attempts have been made to [...] Read more.

In the last 30 years, C–C cross coupling reactions have become a reliable technique in organic synthesis due their versatility and efficiency. While drawbacks have been experienced on an industrial scale with the use of homogenous systems, many attempts have been made to facilitate a heterogeneous renaissance. Thus, this review gives an overview of the current status of the use of heterogeneous catalysts particularly in Suzuki and Heck reactions. Most recent developments focus on palladium immobilised or supported on various classes of supports, thus this review highlights and discuss contributions of the last decade. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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11 pages, 7018 KiB

Open AccessReview

Cobalt-Catalyzed (Hetero)arylation of Saturated Cyclic Amines with Grignard Reagents

by Baptiste Barré, Laurine Gonnard, Amandine Guérinot and Janine Cossy

Molecules 2018, 23(6), 1449; https://doi.org/10.3390/molecules23061449 - 14 Jun 2018

Cited by 9 | Viewed by 4819

Abstract

(Hetero)aryl substituted saturated cyclic amines are ubiquitous scaffolds in biologically active molecules. Metal-catalyzed cross-couplings between halogeno N-heterocycles and organometallic species are efficient and modular reactions to access these attractive scaffolds. An overview of our work concerning the cobalt-catalyzed arylation of iodo-substituted cyclic [...] Read more.

(Hetero)aryl substituted saturated cyclic amines are ubiquitous scaffolds in biologically active molecules. Metal-catalyzed cross-couplings between halogeno N-heterocycles and organometallic species are efficient and modular reactions to access these attractive scaffolds. An overview of our work concerning the cobalt-catalyzed arylation of iodo-substituted cyclic amines is presented. Full article

(This article belongs to the Special Issue Frontiers in Metal-Catalysed Cross-Coupling Reactions for the Synthesis and Functionalisation of Heterocycles)

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