Intramolecular Transfer of Pd Catalyst on Carbon–Carbon Triple Bond and Nitrogen–Nitrogen Double Bond in Suzuki–Miyaura Coupling Reaction

Kamigawara, Takeru; Sugita, Haruo; Mikami, K.; Ohta, Yoshihiro; Yokozawa, Tsutomu

doi:10.3390/catal7070195

Cited by 18 publications

(6 citation statements)

References 18 publications

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“…The reaction of 1 e with 2 a in the presence of 3 afforded exclusively DP through intramolecular transfer of the Pd catalyst on 1 e (Entry 1), whereas MP would be the major product if the additive trapped the Pd catalyst during catalyst transfer on 1 e after the substitution of one of the two bromines in 1 e with 2 a . When styrene and stilbene, which disturbed intramolecular catalyst transfer on dibromostilbene [24] and dibromotolane, [25] were added, DP was almost the only product (Entries 2, 3); it turned out that these olefins cannot trap the Pd catalyst during catalyst transfer on the benzene ring, although they are effective as inhibitors of catalyst transfer on carbon‐carbon multiple bonds.…”

Section: Resultsmentioning

confidence: 99%

Intramolecular Palladium Catalyst Transfer on Benzoheterodiazoles as Acceptor Monomers and Discovery of Catalyst Transfer Inhibitors

Sugita

Kamigawara

Miyazaki

et al. 2023

Chemistry A European J

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Intramolecular catalyst transfer on benzoheterodiazoles was investigated in Suzuki–Miyaura coupling reactions and polymerization reactions with tBu3PPd precatalyst. In the coupling reactions of dibromobenzotriazole, dibromobenzoxazole, and dibromobenzothiadiazole with pinacol phenylboronate, the product ratios of monosubstituted product to disubstituted product were 0/100, 27/73, and 89/11, respectively, indicating that the Pd catalyst undergoes intramolecular catalyst transfer on dibromobenzotriazole, whereas intermolecular transfer occurs in part in the case of dibromobenzoxazole and is predominant for dibromobenzothiadiazole. The polycondensation of 1.3 equivalents of dibromobenzotriazole with 1.0 equivalent of para‐ and meta‐phenylenediboronates afforded high‐molecular‐weight polymer and cyclic polymer, respectively. In the case of dibromobenzoxazole, however, para‐ and meta‐phenylenediboronates afforded moderate‐molecular‐weight polymer with bromine at both ends and cyclic polymer, respectively. In the case of dibromobenzothiadiazole, they afforded low‐molecular‐weight polymers with bromine at both ends. Addition of benzothiadiazole derivatives interfered with catalyst transfer in the coupling reactions.

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Section: Resultsmentioning

confidence: 99%

Intramolecular Palladium Catalyst Transfer on Benzoheterodiazoles as Acceptor Monomers and Discovery of Catalyst Transfer Inhibitors

Sugita

Kamigawara

Miyazaki

et al. 2023

Chemistry A European J

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“…We investigated catalyst transfer on not only aromatic rings, but also multiple bonds between benzene rings in the Suzuki–Miyaura coupling reaction. We found that t Bu 3 PPd moves on a carbon–carbon double bond (C=C) when alkoxy substituents are attached at the ortho ‐position of the benzene rings connected to C=C, and that intramolecular catalyst transfer takes place on a carbon–carbon triple bond and nitrogen–nitrogen double bond even when there are no substituents on the benzene rings . We had focused on catalyst transfer on π‐conjugated systems, and as an extension of that work, we were next interested in whether or not the Pd catalyst can undergo intramolecular catalyst transfer on functional groups located between benzene rings.…”

Section: Methodsmentioning

confidence: 99%

“…We found that tBu 3 PPd moves on a carbon-carbon doubleb ond (C=C) when alkoxy substituents are attached at the ortho-position of the benzene rings connected to C=C, [15] andt hat intramolecularc atalystt ransfer takes place on ac arbon-carbont riple bond and nitrogen-nitrogend ouble bond even when there are no substituents on the benzene rings. [16] We had focused on catalystt ransfer on p-conjugated systems, and as an extension of that work, we were next interested in whether or not the Pd catalystc an undergo intramolecular catalystt ransfer on functional groups located between benzene rings. If this is possible, CTCP could be extended to the synthesis of well-defined engineering plastics containing functionalg roups, such as keto and sulfonyl, as well as ether ands ulfide linkages.…”

mentioning

confidence: 99%

Intramolecular Catalyst Transfer on a Variety of Functional Groups between Benzene Rings in a Suzuki–Miyaura Coupling Reaction

Yokozawa

Harada

Sugita

et al. 2019

Chemistry A European J

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Suzuki–Miyaura coupling reaction of BrC6H4‐X‐C6H4Br 1 (X=CH2, CO, N‐Bu, O, S, SO, and SO2) with arylboronic acid 2 was investigated in the presence of tBu3PPd precatalyst and CsF/[18]crown‐6 as a base to establish whether or not the Pd catalyst can undergo catalyst transfer on these functional groups. In the reaction of 1 (X=CH2, CO, N‐Bu, O, and SO2) with 2, aryl‐disubstituted product 3 (Ar‐C6H4‐X‐C6H4‐Ar) was exclusively obtained, indicating that the Pd catalyst undergoes catalyst transfer on these functional groups. On the other hand, the reaction of 1 e (X=S) and 1 f (X=SO) with 2 afforded only aryl‐monosubstituted product 4 (Ar‐C6H4‐X‐C6H4‐Br) and a mixture of 3 and 4, respectively, indicating that S and SO interfere with intramolecular catalyst transfer. Furthermore, we found that Suzuki–Miyaura polycondensation of 1 (X=CH2, CO, N‐Bu, O, and SO2) and phenylenediboronic acid 5 in the presence of tBu3PPd precatalyst afforded high‐molecular‐weight polymer even when excess 1 was used. The polymers obtained from 1 (X=CH2, N‐Bu, and O) and 5 turned out to be cyclic.

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“…Most high-performing donor–acceptor polymers are synthesized in a step-growth manner from two difunctionalized monomers (e.g., a dihalide and a distannane) using tetrakis(triphenyl)phosphine palladium (Pd(PPh 3 ) 4 ). , Similar to the infancy of palladium-catalyzed small-molecule cross-coupling, , Pd(PPh 3 ) 4 is the workhorse precatalyst for conjugated polymers and is often used despite forming undesired (e.g., homocoupled) byproducts. In Pd-catalyzed small-molecule cross-coupling, however, significant developments in catalyst design have now enabled electron-deficient and -rich substrates with unprotected functional groups to be synthesized with few side products. − While hundreds of ancillary ligands have been screened and optimized for these small-molecule cross-coupling reactions, comparatively few have been explored for synthesizing conjugated polymers, leaving a vast range of potential Pd precatalysts for CTP (Chart ) ,,,− These ligands have been specifically optimized for Pd and, as such, will likely be more successful on Pd than on Ni for CTP . Herein, we highlight select examples of catalysts used in small-molecule cross-couplings as inspiration for expanding CTP.…”

Section: Why Palladium?mentioning

confidence: 99%

The History of Palladium-Catalyzed Cross-Couplings Should Inspire the Future of Catalyst-Transfer Polymerization

2018

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Conjugated polymers are the workhorse materials in organic electronics, a field that is rapidly growing to encompass energy storage devices such as supercapacitors and batteries. The highest-performing materials today have incredibly diverse structures and are accessed via step-growth polymerizations. This method results in limited control over the polymer’s molecular weight, sequence, and dispersity, all of which can significantly impact device performance. The discovery of catalyst-transfer polymerization (CTP) in 2004 was predicted to change this landscape. Instead, nearly 14 years later, the CTP scope remains mostly limited to polymerizing small, electron-rich monomers. There is a pronounced gap between the rich array of structures utilized in organic electronics and what can be polymerized in a living, chain-growth fashion via CTP. Here, we suggest that palladium precatalysts could bridge this gap based on their huge versatility in the small-molecule cross-coupling literature. We highlight specific ancillary ligands from the small-molecule literature that we anticipate are candidates for enabling diverse conjugated polymer syntheses based on nearly a decade of research into the CTP mechanism. In addition, we describe several recent promising examples of CTP mediated by Pd precatalysts that serve as inspiration for the future. We present this Perspective as a call-to-action to advance organic electronics with CTP.

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Intramolecular Transfer of Pd Catalyst on Carbon–Carbon Triple Bond and Nitrogen–Nitrogen Double Bond in Suzuki–Miyaura Coupling Reaction

Cited by 18 publications

References 18 publications

Intramolecular Palladium Catalyst Transfer on Benzoheterodiazoles as Acceptor Monomers and Discovery of Catalyst Transfer Inhibitors

Intramolecular Palladium Catalyst Transfer on Benzoheterodiazoles as Acceptor Monomers and Discovery of Catalyst Transfer Inhibitors

Intramolecular Catalyst Transfer on a Variety of Functional Groups between Benzene Rings in a Suzuki–Miyaura Coupling Reaction

The History of Palladium-Catalyzed Cross-Couplings Should Inspire the Future of Catalyst-Transfer Polymerization

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