Preparation of Partially Substituted 1-Halo- and 1,4-Dihalo-1,3-dienes via Reagent-Controlled Desilylation of Halogenated 1,3-Dienes

Xi, Zhenfeng; Song, Zhiyi; Liu, Guang‐Zhen; Liu, Xiaozhong; Takahashi, Tamotsu

doi:10.1021/jo060003f

Cited by 38 publications

(17 citation statements)

References 22 publications

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“…The DMPVS end group of the C 6 H 5 Si(CH 3 ) 2 CHCH‐capped sPS (prepared in the absence of H 2 ), on the other hand, can undergo a desilylation reaction through treatment with trifluoroacetic acid to provide ethenyl group end‐capped sPS (CH 2 CH‐capped sPS, Fig. 6) with a high yield 18. Consequently, CH 2 CH‐capped sPS can undergo subsequent epoxidation,19 ozonolysis,20 and hydroboration21 to produce epoxide‐capped, formyl‐capped (Fig.…”

Section: Resultsmentioning

confidence: 99%

End‐functionalization of syndiotactic polystyrene by vinylsilane inducing selective chain transfer reactions

Hsiao

Tsai

2010

J. Polym. Sci. A Polym. Chem.

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Structurally well-defined end-functionalized syndiotactic polystyrene (sPS) can be prepared by conducting a simultaneous selective chain transfer reaction during the syndiospecific polymerization of styrene in the presence of vinylsilanes. The production of vinylsilane end-capped sPS involves a unique selective chain transfer pathway via the incorporation of a terminal vinylsilane unit at the polymer chain end by 2,1-insertion. This unusual insertion pattern situates the bulky silyl functional group at a closer b-position from the active catalyst center, thus deactivating the propagating chain by a steric jam between the vinylsilane end group and the active catalyst. Subsequently, chain releasing by hydrogen addition (in the presence of H 2 ) or by b-elimination (in the absence of H 2 ) can take place, which leads to the production of end-functionalized sPS with precise controls of stereoregularity and of the location of functionality.

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Section: Resultsmentioning

confidence: 99%

End‐functionalization of syndiotactic polystyrene by vinylsilane inducing selective chain transfer reactions

Hsiao

Tsai

2010

J. Polym. Sci. A Polym. Chem.

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“…Compounds 3, 5, 8c, and 10a were synthesized according to refs [26,17,27,30], respectively. All reactions working with air-or moisturesensitive compounds were carried out under argon atmosphere using standard Schlenk line techniques.…”

Section: Methodsmentioning

confidence: 99%

“…[28] However, after converting 9a,c into organo-copper species in situ by reaction with CuCl, iodination of the copper species smoothly produced (1Z,3Z)-1,4-diiodo-2,3-diphenylbutadiene derivatives 10a,c with high regio-and stereoselectivity, but moderate yields of 30% for both (Scheme 1b). [28][29][30] 10b was synthesized similarly, but starting from a mixture of 8a and 8b. Because large amounts of homocoupled products rendered the purification process tedious, 10b was isolated in a much lower yield of 12%.…”

Section: Synthesis Of Diphenyl-cp 2a-cmentioning

confidence: 99%

“…Molecular weight data extracted from GPC analysis of polymers PP-Ic, PP-II, PP-IIIa, and PP-IV. [35] To a solution of [(1Z,3Z)-1,4-diiodo-2,3-diphenylbuta-1,3-diene-1,4diyl]bis(trimethylsilane) (10a) [30] (301 mg, 0.500 mmol) in diethyl ether (5 mL) was injected a hexane solution of tBuLi (1.18 mL, 1.7 m, 2.0 mmol) at −78 °C. After stirring at −78 °C for 1 h, CuCl (1.4 mg, 1.05 mmol) was added to the reaction mixture.…”

Section: Synthesis Of 3-(3-ethynylphenyl)-4-phenyl-25-bis[3-(triisopmentioning

confidence: 99%

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Stepwise Lateral Extension of Phenyl‐Substituted Linear Polyphenylenes

Hou

Narita

Müllen

2019

Macro Chemistry & Physics

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and gas-separation [9,10] membranes. Linear PPs with phenyl substituents can also serve as precursors for graphene nanoribbons (GNRs), nano meter-wide strips of graphene. The underlying concept is to appropriately design branched PP structures that can be fully planarized by CC bond formation between the benzene rings, typically through oxidative cyclodehydrogenation. [1,2,11-13] GNRs synthesized by such bottom-up methods have not only contributed to fundamental studies in condensed matter physics, but they also show potential for future applications in nanoelectronics, photonics, and quantum computing. [14-16] One of the most efficient methods to synthesize PPs is through the use of Diels-Alder cycloadditions between cyclopentadienone (CP) derivatives, usually 2,3,4,5-tetraarylcyclopentadienones, and alkynes leading to both linear and dendritic PPs. [1,2] In comparison with other polymerization methods, typically involving transition metal catalyzed or mediated reactions, Diels-Alder reactions, which proceed without metal catalysts or other reagents, also exhibit high efficiency. [12,17] A 2 B 2-type Diels-Alder polymerizations between an A 2 monomer having two CP moieties and a bisalkyne serving as a B 2 monomer have been known for more than 70 years [18,19] and have provided numerous linear PPs with a backbone of poly[(p-phenylene)-ran-(m-phenylene)]. [2] On the other hand, CP derivatives carrying an alkyne functional group can serve as bifunctional monomers that undergo AB-type Diels-Alder polymerization to yield linear PPs with surprisingly high persistence length. [17,20] Moreover, PPs synthesized by this procedure exhibit higher degrees of polymerizations (DP) than those made by A 2 B 2-type polymerization. [17,21,22] In 2014, we have reported an AB-type Diels-Alder polymerization of tetraphenyl-CP 1a leading to linear PP-Ia with the poly[(p-phenylene)-ran-(m-phenylene)] backbone (Figure 1a). The weight-average molecular weight (M w) of PP-Ia exceeded 600 000 g mol −1 , which was much larger than values obtained with previous PPs prepared by A 2 B 2-type Diels-Alder polymerization. The structure of PP-Ia can be projected into a plane without spatial overlap of benzene rings. "Planarization" of PP-Ia through oxidative cyclodehydrogenation could thus provide structurally defined GNRs. [17] Moreover, we have demonstrated the synthesis of laterally extended linear PP-Ib using CP-based monomer 1b with Polyphenylenes (PPs) are unique polymers showing high mechanical strength and chemical stability, and having potential applications, for example, in proton transfer and gas-separation membranes. Moreover, phenyl-substituted linear PPs can serve as precursors for bottom-up syntheses of graphene nanoribbons (GNRs), a new class of nanoscale carbon materials that appear promising for nanoelectronics. Notably, lateral extensions of linear PPs with appropriate "branched" phenyl substituents, that is, avoiding spatial overlap of benzene rings in their projections into a plane, can lead to wider GNRs with modulated elect...

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“…These results indicate clearly that the configurational inversion of the C=C double bond should exist in this reaction process. Synthesis of the two pure isomers 13 a [20][21] and 13 b [21][22] is shown in Scheme 10. Scheme 6.…”

Section: Identification Of the Configurational E/z Isomerization As Amentioning

confidence: 99%

Formation of α‐Lithio Siloles from Silylated 1,4‐Dilithio‐1,3‐Butadienes: Mechanism and Applications

Luo¹,

Wang²,

Gu³

et al. 2010

Chemistry An Asian Journal

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A full account of a useful transformation from silylated 1,4-dilithio-1,3-butadienes to alpha-lithio siloles is described. These lithio siloles formed by this procedure are general, in terms of substitution patterns and synthetic methods, affording diversified silole derivatives. Notably, some structurally complex molecules, such as bridged bis-silole compounds, have been synthesized easily and successfully by applying our protocol. The structure of the alpha-lithio silole, which adopts a dimeric fashion through two lithium bridges, was confirmed by X-ray analysis. Furthermore, a possible mechanism of the skeleton rearrangements via E/Z isomerization of 1-silyl-1-lithio alkene and nucleophilic attack on silicon is proposed, and is also proved by experimental investigations.

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Preparation of Partially Substituted 1-Halo- and 1,4-Dihalo-1,3-dienes via Reagent-Controlled Desilylation of Halogenated 1,3-Dienes

Cited by 38 publications

References 22 publications

End‐functionalization of syndiotactic polystyrene by vinylsilane inducing selective chain transfer reactions

End‐functionalization of syndiotactic polystyrene by vinylsilane inducing selective chain transfer reactions

Stepwise Lateral Extension of Phenyl‐Substituted Linear Polyphenylenes

Formation of α‐Lithio Siloles from Silylated 1,4‐Dilithio‐1,3‐Butadienes: Mechanism and Applications

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