Modular Approach to Silicon‐Bridged Biaryls: Palladium‐Catalyzed Intramolecular Coupling of 2‐(Arylsilyl)aryl Triflates

Shimizu, Masaki; Mochida, Kenji; Hiyama, Tamejiro

doi:10.1002/anie.200804146

Cited by 172 publications

(83 citation statements)

References 82 publications

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“…The groups of Murakami [4] and Shimizu [5] independently reported the pioneering construction of a silole moiety in the presence of a metal catalyst. These protocols were limited by high reaction temperatures and multistep procedures for the preparation of the starting materials.…”

mentioning

confidence: 99%

Versatile Synthesis of Blue Luminescent Siloles and Germoles and Hydrogen‐Bond‐Assisted Color Alteration

Yabusaki

Ohshima

Kondo

et al. 2010

Chemistry A European J

114

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Group 14 metalloles are an interesting class of Si-, Ge-, or Sn-based annulated p-conjugated molecules.[1] The silole ring system contains a s* orbital on the silicon atom, which effectively interacts with the p* orbital of the butadiene unit, producing a low-lying LUMO. Although a variety of sophisticated silole derivatives have been prepared, the preparation of these well-designed compounds depends heavily on classical Si À C bond-formation methods by using highly reactive organometallic reagents (Scheme 1a). [2,3] This procedure is not always simple, nor is it safe to implement, from the perspective of its applications.Recently, a transition-metal-catalyzed process has been developed to overcome these problems. The groups of Murakami [4] and Shimizu [5] independently reported the pioneering construction of a silole moiety in the presence of a metal catalyst. These protocols were limited by high reaction temperatures and multistep procedures for the preparation of the starting materials. Thus, the development of mild and general methods for the preparation of silole derivatives has remained an important goal. During development of organosilicon compounds containing an aromatic ring, we identified a new methodology based on transition-metal-catalyzed arylation of hydrosilanes with aryl halides.[6] Herein, we report a novel method for constructing the skeletons of Group 14 metalloles from the corresponding dihydrosilanes or dihydrogermanes using Pd-catalyzed E À C (E= Si, Ge) bond formation (Scheme 1b). The effects of the substituents on the physical properties of these materials will be discussed in detail.We examined the cyclic double intramolecular arylation of a 2,2'-diiodobiaryl with a secondary silane in the presence of the base (iPr) 2 EtN, using [Pd(PA C H T U N G T R E N N U N G (tBu) 3 ) 2 ] as the catalyst. [7,8] The results are shown in Scheme 2. The reaction proceeded smoothly to produce the desired dibenzosiloles or -germoles as colorless solids in good to high yields (1-16). The reaction described herein provides a unique method for the preparation of Group 14 metalloles containing a reactive functional group on the aromatic rings, some of which (13-16) are difficult to synthesize when using conventional synthetic methods. 2,2'-Diiodobithiophene gave an inferior yield for product 17; the reduced product was favored. Unfortunately, the intramolecular cyclization of 1-NpPhSiH 2 (Np = naphthyl) or (tBu) 2 SiH 2 with 2,2'-diiodobiphenyl did not occur at all under the present conditions due to the steric crowding of the secondary silanes.The photophysical properties of compounds 1-17 were determined by UV-visible and fluorescence spectroscopies, collected in dichloromethane or in the corresponding crystalline state. These results are summarized in Table 1. The UVvisible absorption spectra showed that the position of the

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mentioning

confidence: 99%

Versatile Synthesis of Blue Luminescent Siloles and Germoles and Hydrogen‐Bond‐Assisted Color Alteration

Yabusaki

Ohshima

Kondo

et al. 2010

Chemistry A European J

114

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“…Recently Shimizu et al reported on a novel and versatile approach to SBArs which involves Pd-catalyzed intramolecular direct arylation of readily available 2-(arylsilyl)aryl triflates ( Fig. 22) [87]. This approach is applicable to the facile synthesis of not only symmetrical and asymmetrical functionalized 9-silafluorenes, but also SBArs containing heteroaromatic rings, such as furan, thiophene, and pyrrole.…”

Section: Ts Bsmentioning

confidence: 98%

Conjugated Organosilicon Materials for Organic Electronics and Photonics

Ponomarenko

Kirchmeyer

2010

Advances in Polymer Science

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In this chapter different types of conjugated organosilicon materials possessing luminescent and/or semiconducting properties will be described. Such macromolecules have various topologies and molecular structures: linear, branched and hyperbranched oligomers, polymers, and dendrimers. Specific synthetic approaches to access these structures will be discussed. Special attention is devoted to the role of silicon in these structures and its influence on their optical and electrical properties, leading to their potential application in the emerging areas of organic and hybrid electronics.

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“…Many of them have high fluorescence efficiencies in solid films, and show great potential in OLEDs. [4,5] Among numerous AIE luminogens, [6,7] siloles exhibit typical AIE effect with high fluorescence efficiencies in the aggregated state, and have a wide range of high-tech applications, such as chemosensors, bioprobes, and OLEDs. [8][9][10] Moreover, siloles own unique electron structure of σ*-π* conjugation between the σ* orbitals of two exocyclic silicon-carbon bonds and π* orbital of the butadiene moiety.…”

Section: Introductionmentioning

confidence: 99%

A Silole‐Based Efficient Electroluminescent Material with Good Electron‐Transporting Potential

Quan

Qin

et al. 2015

Chin. J. Chem.

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A new silole derivative, 2,5-bis(7-(dimesitylboranyl)-9,9-dimethylfluoren-2-yl)-1-methyl-1,3,4-triphenylsilole ((MesBF) 2 MTPS), is synthesized and characterized. (MesBF) 2 MTPS shows a good fluorescence efficiency of 15% in THF solution and a higher efficiency of 86% in solid film, presenting an aggregation-enhanced emission characteristic. It is thermally and morphologically stable, with high decomposition and glass-transition temperatures of 257 and 171 ℃, respectively. The LUMO energy level (−2.96 eV) of (MesBF) 2 MTPS is lower than that of TPBi, revealing its electron-transporting potential. Efficient organic light-emitting diodes (OLEDs) are fabricated using (MesBF) 2 MTPS as emitter, which radiates yellow light at 554 nm, and affords high maximum luminance, current efficiency, and external quantum efficiency of 48348 cd•m −2 , 12.3 cd•A −1 , and 4.1%, respectively.

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Modular Approach to Silicon‐Bridged Biaryls: Palladium‐Catalyzed Intramolecular Coupling of 2‐(Arylsilyl)aryl Triflates

Cited by 172 publications

References 82 publications

Versatile Synthesis of Blue Luminescent Siloles and Germoles and Hydrogen‐Bond‐Assisted Color Alteration

Versatile Synthesis of Blue Luminescent Siloles and Germoles and Hydrogen‐Bond‐Assisted Color Alteration

Conjugated Organosilicon Materials for Organic Electronics and Photonics

A Silole‐Based Efficient Electroluminescent Material with Good Electron‐Transporting Potential

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