Palladium‐Catalyzed Synthesis of Heteroarene‐Fused Cyclooctatetraenes through Dehydrogenative Cyclodimerization

Fukuzumi, Keita; Nishii, Yuji; Miura, Masahiro

doi:10.1002/ange.201707515

Cited by 26 publications

(4 citation statements)

References 53 publications

(33 reference statements)

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“…The best oxidant was AgBF 4 , which afforded the desired tetrapyrrole 16 in a moderate yield of 21 % (Scheme 6). [23] Tetramers with more electron-rich bispyrroles as starting materials were identified by mass spectrometry, but we were unable to isolate them. Scheme 6.…”

Section: Resultsmentioning

confidence: 96%

Reactions of 3,3′‐Linked Bispyrroles with Carbon Electrophiles

2019

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The reactivity of 3,3′‐linked bispyrroles, easily accessible by ring‐enlargement reactions of donor–acceptor cyclopropanes, towards various carbon electrophiles was investigated. A biscyclopropanated furan, equipped with imines as acceptor units, was converted by rearrangement and subsequent elimination of water to 3,3′‐linked bispyrroles. Thereby the nucleophilic 2‐position of the pyrroles stayed unsubstituted, thus permitting a further reaction with electrophiles. The heterocycles were treated with oxalyl chloride to form a new six‐membered ring between the pyrrolic subunits. The 1,2‐diketone moiety in these species was used as a starting point to extend the π‐system via a condensation reaction with aromatic 1,2‐diamines. The reaction of 3,3′‐linked bispyrroles with the phosgene surrogate triphosgene led to a seven‐membered anhydride. The use of the Vilsmeier reagent led to a formylation of the bispyrroles. Furthermore, a direct oxidative coupling between two bispyrroles resulted in a previously unknown linkage (3,3′:2′,2′′:3′′,3′′′) between four pyrrole subunits.

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Section: Resultsmentioning

confidence: 96%

Reactions of 3,3′‐Linked Bispyrroles with Carbon Electrophiles

2019

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“…Three low-angle diffraction peaks were observed at 2θ = 3.64, 7.34, and 11.1°(S phase) and 3.04, 6.15, and 9.26°(M phase), which corresponded to the formation of lamellar structures with d 001 distances of 24.2 and 29.0 Å, respectively. To understand the molecular assemblies in the lamellar structures, we performed a single-crystal structure analysis of tetra [2,3]thienylene tatracarboxylic acid tetraethyl ester 2′, 33 which is the precursor of 5. S3), which contributed to stabilize the M phase.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Dynamic Motion of Twisted π System-Induced Temperature-Dependent Dielectric Response in the Neat Liquid State

2019

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Molecular assemblies of twisted π molecules of tetraphenylene with long alkoxy chains (1) and tetra[2,3]thienylene with long alkylamide chains (2) or long alkoxy chains (3) and their dielectric properties were investigated. Different degrees of intermolecular interaction of 1–3 afforded different molecular assemblies, including an ordered columnar structure, disordered columnar, and lamellar structures. The introduction of long alkyl chains enabled us to create thermally stable liquid crystalline or liquid states. Temperature-dependent dielectric measurement revealed that the dynamic flipping motion of the tetra[2,3]thienylene core of 3 induced a temperature- and frequency-dependent dielectric anomaly in the neat liquid phase. This flipping motion of the central tetra[2,3]thienylene π core occurred relatively easily in the liquid state with a high degree of freedom of molecular motion.

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“…However, C-H activation methods to develop π-conjugated materials based on thiophene homocoupling are highly scarce. Only π-extended regioregular polythiophene polymers [17][18][19] and heteroarene-fused cyclooctatetraenes 20 via dehydrogenative cyclo-dimerization are known so far. Moreover, the developed methods require either stoichiometric amounts of an Ag(I) oxidant or specialized ancillary ligands, limiting the largescale synthesis of compounds.…”

Section: Introductionmentioning

confidence: 99%