3.7. Palladium Nanoparticles as Catalysts 888 3.8. Other Transition-Metal Complexes 888 3.9. Transition-Metal-Free Reactions 889 4. Applications 889 4.1. Alkynylation of Arenes 889 4.2. Alkynylation of Heterocycles 891 4.3. Synthesis of Enynes and Enediynes 894 4.4. Synthesis of Ynones 896 4.5. Synthesis of Carbocyclic Systems 897 4.6. Synthesis of Heterocyclic Systems 898 4.7. Synthesis of Natural Products 903 4.8. Synthesis of Electronic and Electrooptical Molecules 906

https://www.chem.ccu.edu.tw/~joyce/referance/ericyang/Chem.%20Rev/Chem.%20Rev.%202007,%20107,%20874-922.pdf

The Sonogashira Reaction: A Booming Methodology in Synthetic Organic Chemistry†

Departament of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneve 4, Switzerland, Department of Organic Chemistry, Stockholm University, Arrhenius Laboratoriet, 106 91 Stockholm, Sweden, Organic Chemistry II, Dormund University of Technology, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany, and Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgili, C/ Marcel · li Domingo s/n, 43007 Tarragona, Spain

Enantioselective Copper-Catalyzed Conjugate Addition and Allylic Substitution Reactions

Catalytic Enantioselective Formation of C−C Bonds by Addition to Imines and Hydrazones: A Ten-Year Update

Introduction: Branched macromolecules or dendrimers have provided a rich seam of research in terms of both innovative chemistry and applications.1-14 For example, dendrimers have been studied for use as low-dielectric materials,15 as templates for the growth of single-wall carbon nanotubes,16 as catalysts,17-19 and in biological applications,20-23 including biosensors,24 magnetic resonance imaging,25-28 and drug delivery.29-33 However, it has only been more recently that such macromolecular structures have been explored in terms of their electronic and optoelectronic properties, which is the focus of this series of reviews. For example, charge-transporting dendrimers have become an important class of organic semiconducting material34 and significant effort has focused on light harvesting and energy transfer from a peripheral dye or chromophore to an emissive dye at the center or focus of the dendrimer.35-39 Organic semiconductors have become increasingly important as the active component in applications including organic light-emitting diodes (OLEDs),40-42 transistors,43,44 photovoltaic (PV) cells,45,46 optical amplifiers,47,48 and lasers.49-51 Traditionally, organic semiconductors have fallen into two main classes, small molecules and polymers, and these materials and their applications will be covered in detail by other authors. Small molecules are generally processed by evaporation techniques and have the advantages that the structure−property relationships are relatively simple to understand, the materials are mono(disperse), and they are deposited in a pure form. On the other hand, conjugated polymers are soluble and can be deposited from solution by processes such as spin-coating and ink-jet printing, which opens up the exciting prospect of simple, fast, large-area, low-temperature device manufacturing. An additional advantage for conjugated polymers is that solution processing is potentially less wasteful of material than evaporation for devices that require patterning. However, it is often difficult to control the polydispersity, molecular weight, backbone defects, and end groups of conjugated polymers reproducibly. Branched macromolecules, known as dendrimers, also have the advantage of being solution processable but by careful design can incorporate the control over the optoelectronic properties that is reminiscent of small molecules. In addition, the dendritic architecture provides a number of other attractive properties, including the ability to independently control the processing and optoelectronic properties; providing the processing power to enable simple chromophores to be deposited as stable amorphous films; dendrimer generation as a tool for controlling the intermolecular interactions that govern device performance; and the ability in well-defined dendrimers to have high chemical purity. In this review, we will focus on synthetic strategies that have been investigated for the preparation of optoelectronically active solution-processable dendritic materials and concentrate on two different applications, namely OLEDs and solar cells, in which they have been used. In the context of OLEDs, we limit the discussion to light emission, as branched macromolecules for charge transport will be discussed in the review by Shirota. We will also briefly comment on other recent light-emitting and -absorbing branched molecular materials that have been used in OLEDs and solar cells.

Development of Dendrimers: Macromolecules for Use in Organic Light-Emitting Diodes and Solar Cells

Asymmetric catalysis with transition-metal complexes is the basis for a vast array of stereoselective transformations and has changed the face of modern synthetic chemistry. Key to this success has been the design of chiral ligands to control the regio-, diastereo-, and enantioselectivity. Phosphoramidites have emerged as a highly versatile and readily accessible class of chiral ligands. Their modular structure enables the formation of ligand libraries and easy fine-tuning for a specific catalytic reaction. Phosphoramidites frequently show exceptional levels of stereocontrol, and their monodentate nature is essential in combinatorial catalysis, where a ligand-mixture approach is used. In this Review, recent developments in asymmetric catalysis with phosphoramidites used as ligands are discussed, with a focus on the formation of carbon-carbon and carbon-heteroatom bonds.

Phosphoramidites: Privileged Ligands in Asymmetric Catalysis

A Copper(II)‐Catalyzed Aza‐Friedel–Crafts Reaction of N‐(2‐Pyridyl)sulfonyl Aldimines: Synthesis of Unsymmetrical Diaryl Amines and Triaryl Methanes

An efficient chiral Lewis acid-catalyzed inverse-electron-demand Diels−Alder reaction of 1-azadienes is described. This procedure is based on the combination of NiII-DBFOX complex as catalyst and the use of a metal-coordinating (8-quinolyl)sulfonyl moiety at the iminic nitrogen of the N-sulfonyl 1-aza-1,3-diene, providing highly functionalized piperidine derivatives in good yields with excellent endo-selectivity, and enantioselectivities typically in the range of 77−92% ee.

Catalytic asymmetric inverse-electron-demand Diels-Alder reaction of N-sulfonyl-1-aza-1,3-dienes.

The enantioselective catalytic 1,4-addition to α,β-unsaturated ketimines is an unprecedented process. Herein, we document the copper-catalyzed addition of dialkylzinc reagents to (2-pyridylsulfonyl)imines of chalcones. This process occurs rapidly in the presence of a chiral phosphoramidite ligand to afford exclusively the 1,4-addition product. In the case of addition of dimethylzinc, enantioselectivities in the range 70−80% ee are obtained. The presence of the metal-coordinating 2-pyridylsulfonyl group proved to be essential for this reaction to proceed.

Copper-catalyzed enantioselective conjugate addition of dialkylzinc reagents to (2-pyridyl)sulfonyl imines of chalcones.

The different behavior of N-tosyl imines and N-(2-pyridyl)sulfonyl imines in CuII-catalyzed AFCR is described. DFT theoretical calculations on the mode of coordination of the copper atom to both types of substrates allow understanding this different reactivity.

Understanding the behavior of N-tosyl and N-2-pyridylsulfonyl imines in CuII-catalyzed aza-Friedel-Crafts reactions.

Nanometer-sized conjugated 1,4- and 1,3,5-ethynylphenyl oligomers were synthesized starting from 3,5-di(trimethylsilylethynyl)phenylacetylene and p-[3,5-di(trimethylsilylethynyl)-1-ethynylphenyl]phenyl acetylene by cross-coupling reaction with a convenient haloaryl derivative, catalyzed by palladium(II)/copper(I), in excellent yield. The terminal acetylenes were efficiently prepared by a specific protection-deprotection methodology. All ethynylphenyl homologues obtained show fluorescence emission, with the bathochromic shift of approximately 20 nm by each ethynylphenyl unit increasing the conjugate chain. Parallel conjugated ethynylphenyl chains were prepared through the insertion of a 1,5-naphthalene subunit, and the compounds exhibit fluorescence radiation emission.

Jorge Esquivias

Papers

A Copper(II)‐Catalyzed Aza‐Friedel–Crafts Reaction of N‐(2‐Pyridyl)sulfonyl Aldimines: Synthesis of Unsymmetrical Diaryl Amines and Triaryl Methanes

Catalytic asymmetric inverse-electron-demand Diels-Alder reaction of N-sulfonyl-1-aza-1,3-dienes.

Copper-catalyzed enantioselective conjugate addition of dialkylzinc reagents to (2-pyridyl)sulfonyl imines of chalcones.

Understanding the behavior of N-tosyl and N-2-pyridylsulfonyl imines in CuII-catalyzed aza-Friedel-Crafts reactions.

Synthesis of Nanostructures Based on 1,4- and 1,3,5-Ethynylphenyl Subunits with π-Extended Conjugation. Carbon Dendron Units