-phenylenevinylene)s L4. Fluorene-Based Conjugated Polymers L4.1. Fluorene-Based Copolymers ContainingElectron-Rich MoietiesM4.2. Fluorene-Based Copolymers ContainingElectron-Deﬁcient MoietiesN4.3. Fluorene-Based Copolymers ContainingPhosphorescent ComplexesQ5. Carbazole-Based Conjugated Polymers R5.1. Poly(2,7-carbazole)-Based Polymers R5.2. Indolo[3,2-

https://ir.nctu.edu.tw:443/bitstream/11536/6508/1/000271856900020.pdf

Synthesis of Conjugated Polymers for Organic Solar Cell Applications

Pick your Pd partners: A number of catalytic systems have been developed for palladium-catalyzed CH activation/CC bond formation. Recent studies concerning the palladium(II)-catalyzed coupling of CH bonds with organometallic reagents through a PdII/Pd0 catalytic cycle are discussed (see scheme), and the versatility and practicality of this new mode of catalysis are presented. Unaddressed questions and the potential for development in the field are also addressed.

In the past decade, palladium-catalyzed CH activation/CC bond-forming reactions have emerged as promising new catalytic transformations; however, development in this field is still at an early stage compared to the state of the art in cross-coupling reactions using aryl and alkyl halides. This Review begins with a brief introduction of four extensively investigated modes of catalysis for forming CC bonds from CH bonds: PdII/Pd0, PdII/PdIV, Pd0/PdII/PdIV, and Pd0/PdII catalysis. A more detailed discussion is then directed towards the recent development of palladium(II)-catalyzed coupling of CH bonds with organometallic reagents through a PdII/Pd0 catalytic cycle. Despite the progress made to date, improving the versatility and practicality of this new reaction remains a tremendous challenge.

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Palladium(II)-catalyzed C-H activation/C-C cross-coupling reactions: versatility and practicality.

/pdf/aryl-aryl-bond-formation-one-century-after-the-discovery-of-1jdyxlkwix.pdf

Aryl-aryl bond formation one century after the discovery of the Ullmann reaction.

Privileged substructures are of potentially great importance in medicinal chemistry. These scaffolds are characterized by their ability to promiscuously bind to a multitude of receptors through a variety of favorable characteristics. This may include presentation of their substituents in a spatially defined manner and perhaps also the ability to directly bind to the receptor itself, as well as exhibiting promising characteristics to aid bioavailability of the overall molecule. It is believed that some privileged substructures achieve this through the mimicry of common protein surface elements that are responsible for binding, such as β- and gamma;-turns. As a result, these structures represent a promising means by which new lead compounds may be identified.

The combinatorial synthesis of bicyclic privileged structures or privileged substructures

In studying the evolution of organic chemistry and grasping its essence, one comes quickly to the conclusion that no other type of reaction plays as large a role in shaping this domain of science than carbon-carbon bond-forming reactions. The Grignard, Diels-Alder, and Wittig reactions are but three prominent examples of such processes, and are among those which have undeniably exercised decisive roles in the last century in the emergence of chemical synthesis as we know it today. In the last quarter of the 20th century, a new family of carbon-carbon bond-forming reactions based on transition-metal catalysts evolved as powerful tools in synthesis. Among them, the palladium-catalyzed cross-coupling reactions are the most prominent. In this Review, highlights of a number of selected syntheses are discussed. The examples chosen demonstrate the enormous power of these processes in the art of total synthesis and underscore their future potential in chemical synthesis.

Palladium-catalyzed cross-coupling reactions in total synthesis.

The cross-coupling of organotin reagents with a variety of organic electrophiles, catalyzed by palladium, provides a novel method for generating a carbon-carbon bond. Because this mild, versatile reaction is tolerant of a wide variety of functional groups on either coupling partner, is stereospecific and regioselective, and gives high yields of product, it is ideal for use in the synthesis of elaborate organic molecules. When the coupling reaction is carried out in the presence of carbon monoxide, instead of a direct coupling, carbon monoxide insertion takes place, stitching the two coupling partners together and generating a ketone.

The Palladium‐Catalyzed Cross‐Coupling Reactions of Organotin Reagents with Organic Electrophiles [New Synthetic Methods (58)]

Palladium-katalysierte Kupplungsreaktionen von Organozinn-Verbindungen mit unterschiedlichsten organischen Elektrophilen sind eine relativ neue Methode zur Knupfung von Kohlenstoff-Kohlenstoff-Bindungen. Da sie unter milden Bedingungen ablauft und eine Vielfalt funktioneller Gruppen an jedem der beiden Reaktionspartner ermoglicht, daruber hinaus stereospezifisch, regioselektiv und in hohen Ausbeuten verlauft, eignet sie sich ideal fur die Synthese komplizierter organischer Verbindungen. Wird die Kupplungsreaktion in Gegenwart von Kohlenmonoxid ausgefuhrt, so findet eine Verknupfung der beiden Reaktanten unter Kohlenmonoxid-Insertion statt, so das man Ketone erhalt.

Palladium-katalysierte Kupplungsreaktionen organischer Elektrophile mit Organozinn-Verbindungen

The hydroformylation reaction — the addition of dihydrogen and carbon monoxide to an alkene or alkyne to produce an aldehyde — is one of the most important industrial chemical reactions. It is remarkable in that it converts simple, inexpensive starting materials into useful products. A new carbon–carbon bond is formed along with a very useful and reactive functionality.

Hydroformylation and Related Additions of Carbon Monoxide to Alkenes and Alkynes

The reaction product of m-cresol and phosphorus pentoxide has been shown by 31P-nmr to consist of an equimolar mixture of mono- and di-m-cresyl phosphate. A mixture of pure di-m-cresyl phosphate and m-cresol is an excellent polymerization medium for the preparation of polyquinolines via the Friedlander reaction, giving higher-molecular-weight polymers than can be obtained from the crude reaction of m-cresol and phosphorus pentoxide. Spin-lattice relaxation times T1 have been used to relate the chain mobility of the polymers in solution to the glass transition temperature (Tg) in the solid.

John K. Stille

Papers

The Palladium‐Catalyzed Cross‐Coupling Reactions of Organotin Reagents with Organic Electrophiles [New Synthetic Methods (58)]

Palladium-katalysierte Kupplungsreaktionen organischer Elektrophile mit Organozinn-Verbindungen

Hydroformylation and Related Additions of Carbon Monoxide to Alkenes and Alkynes

Polyquinolines: A class of rigid‐chain polymers

Book Review: Tin in Organic Synthesis. By M. Pereyre, J.‐P. Quintard, and A. Rahm