Shape‐Persistent Macrocycles: A Synthetic Strategy that Combines Easy and Site‐Specific Decorations with Improved Cyclization Efficiency

Sakamoto, Junji; Schlüter, A. Dieter

doi:10.1002/ejoc.200700118

Cited by 30 publications

(11 citation statements)

References 35 publications

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“…On the other hand, when the reaction was performed under cuprous‐free conditions, the yield of 1 surprisingly increased to about 45 %. This result is consistent with our previous observation in other macrocycle synthesis: the absence of CuI from the Sonogashira reaction can have a positive impact on the cyclization efficiency 20b. Even though the reaction proceeded rather slowly and therefore required more Pd catalyst for its acceleration, GPC analysis of the products clearly indicated grossly reduced formation of the oligomeric side products (see the Supporting Information).…”

Section: Methodssupporting

confidence: 92%

Rational Monomer Design towards 2D Polymers: Synthesis of a Macrocycle with Three 1,8‐Anthrylene Units

Kissel

Schlüter

Sakamoto

2009

Chemistry A European J

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An iterative synthesis of a macrocycle with three 1,8‐anthrylene units (see picture, R=C6H13) was achieved by using Pd‐catalyzed cross‐coupling protocols, in which a copper‐free Sonogashira reaction was the key to the final cyclization. Photochemical model reactions suggest that the macrocycle has the potential to undergo photo‐induced [4+4] cycloaddition without undesired side reactions, which is of relevance for the ultimate goal of creating 2D polymers.

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Section: Methodssupporting

confidence: 92%

Rational Monomer Design towards 2D Polymers: Synthesis of a Macrocycle with Three 1,8‐Anthrylene Units

Kissel

Schlüter

Sakamoto

2009

Chemistry A European J

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“…Although Pd-catalyzed C À C coupling reactions have widely been used to modify macrocyclic ligands like porphyrins, porphyrazins or phthalocyanines, [20] literature examples of coupling reactions catalyzed by Pd macrocycles are seldom. Only in recent years have the first examples of such reactions been published.…”

Section: Introductionmentioning

confidence: 99%

Macrocyclic Palladium(II) Complexes in CC Coupling Reactions: Efficient Catalysis by Controlled Temporary Release of Active Species

Röhlich¹,

Köhler²

2010

Adv Synth Catal

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Stabilization of palladium species against agglomeration is essential for reasonable catalytic activity in C À C coupling reactions. In contrast to common methods of palladium(0) complex or particle stabilization, a new concept is introduced here: it is demonstrated that a controlled release of palladium from an inactive precatalyst provides stability, too, and leads to high catalytic activity. This paper presents surprising catalytic results for Heck and Suzuki reactions with aryl chlorides and bromides, using three highly stable macrocyclic palladium complexes as catalyst precursors. Three different behaviour patterns for the macrocyclic complexes can be deduced from the evaluation of catalytic activities, UV-Vis spectroscopy, recycling studies of immobilized complexes, and ligand addition experiments. (i) Palladium tetraphenylporphyrin reversibly releases only extremely low amounts of palladium during the reactions, and low coupling activities are observed.(ii) Release of palladium from its phthalocyanine complex is irreversible; cumulative release of palladium into the reaction mixtures leads to high catalytic activity. (iii) Extraordinary results were obtained with a Robson-type complex of palladium, which reversibly releases effectual amounts of palladium into solution under reaction conditions. This controlled release prevents the formation of inactive palladium agglomerates under harsh conditions and leads to high catalytic performances. Even strongly deactivated electron-rich aryl chlorides (4-chloroanisole) can be completely and selectively converted by the in situ formed anionic palladium halide complexes; the addition of typical stabilizing additives (TBAB) was found to be unnecessary. The bimetallic palladium complex is regenerated at the end of the reaction. These results contribute to the current understanding of the active species in C À C coupling reactions of Heck and Suzuki types.

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“…[30]). When F5 was subjected to recycling GPC (recGPC), [31,32] however, a shoulder appeared after the fourth cycle, which developed into a distinct peak upon increasing the number of cycles (Fig. 1c).…”

mentioning

confidence: 99%

Side‐Chain Degradation of Ultrapure π‐Conjugated Oligomers: Implications for Organic Electronics

et al. 2009

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Shape‐Persistent Macrocycles: A Synthetic Strategy that Combines Easy and Site‐Specific Decorations with Improved Cyclization Efficiency

Cited by 30 publications

References 35 publications

Rational Monomer Design towards 2D Polymers: Synthesis of a Macrocycle with Three 1,8‐Anthrylene Units

Rational Monomer Design towards 2D Polymers: Synthesis of a Macrocycle with Three 1,8‐Anthrylene Units

Macrocyclic Palladium(II) Complexes in CC Coupling Reactions: Efficient Catalysis by Controlled Temporary Release of Active Species

Side‐Chain Degradation of Ultrapure π‐Conjugated Oligomers: Implications for Organic Electronics

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