Tellurium-Mediated Halogen Transfer from Polyhaloalkanes to Diyne Acceptors

Blum, Jochanan; Baidossi, Waeel; Badrieh, Yacoub; Hoffman, Ralph E.; Schumann, Herbert

doi:10.1021/jo00120a015

Cited by 42 publications

(11 citation statements)

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“…The yield of 1bb was 85%. This method was later applied for the preparation of dibenzopentalenes 1cc-1ff (Scheme 15) [38]. When PdCl 2 was used as a catalyst, a Pd-complex of 1bb was isolated and treatment of the resulting complex with triphenylphosphine provided 1bb, even though the yield was very low.…”

Section: Preparation Of Dibenzopentalenes In the Presence Of Catalystsmentioning

confidence: 99%

“…When the reactions were carried out in the presence of dialkyl acetylenedicarboxylates, the corresponding adducts 1gg-1ii were obtained (2536% yields) together with 1bb (Scheme 16) [40]. The cyclization reactions of 1,2-bis(phenylethynyl)benzenes to afford dibenzopentalenes were surprisingly catalyzed by tellurium (Scheme 17) [38]. Heating of 29a with a catalytic amount of tellurium in pentachloroethane (PCE) under reflux provided dibenzopentalene 1jj in 61% yield through a halogen transfer reaction (Scheme 17).…”

Section: Preparation Of Dibenzopentalenes In the Presence Of Catalystsmentioning

confidence: 99%

“…Heating of 29a with a catalytic amount of tellurium in pentachloroethane (PCE) under reflux provided dibenzopentalene 1jj in 61% yield through a halogen transfer reaction (Scheme 17). When 29a was heated with a catalytic amount of tellurium in tetrabromoethane at 170 °C, the corresponding bromodibenzopentalene 1kk was obtained in 6% yield (Scheme 18) [38]. Treatment of 29b with a catalytic amount of tellurium in PCE under reflux produced a 1:1 mixture of 1ll and 1mm in 79% yield.…”

Section: Preparation Of Dibenzopentalenes In the Presence Of Catalystsmentioning

confidence: 99%

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Synthesis and Reactions of Dibenzo[a,e]pentalenes

Saito

2010

Symmetry

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Pentalene has recently received a considerable amount of attention as a ligand in sandwich-type transition metal complexes. In contrast, dibenzo[a,e]pentalene (hereafter denoted as dibenzopentalene), which is more -extended than pentalene, has received less attention, despite its potential usefulness as a building block of ladder-type -conjugated molecules, which have recently received growing interest. However, very recently, several novel efficient methods for the synthesis of dibenzopentalenes have been reported. This review surveys recent advances in the synthesis and reactions of dibenzopentalenes and describes the aromaticity of their ionic species.

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Section: Preparation Of Dibenzopentalenes In the Presence Of Catalystsmentioning

confidence: 99%

Section: Preparation Of Dibenzopentalenes In the Presence Of Catalystsmentioning

confidence: 99%

Section: Preparation Of Dibenzopentalenes In the Presence Of Catalystsmentioning

confidence: 99%

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Synthesis and Reactions of Dibenzo[a,e]pentalenes

Saito

2010

Symmetry

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“…Pentalenes are 8π-antiaromatic polycyclic hydrocarbons (PAHs) used as active organic optoelectronic materials (e.g., OLED and OFET), semiconductors, and ligands in transition metal complexes. Since 1912, numerous studies have explored the dibenzopentalene (DBP) structures and characterized their physical properties because of their interesting antiaromatic properties, paratropic current, extended π-conjugation, and narrow HOMO/LUMO energy gap . The molecular framework of DBPs, such as dibenzo[ a , e ]pentalene, dihydrobenzo[ a , e ]pentalene, and dibenzo[ a , f ]pentalene, has a benzene ring annulated on the pentalene face (Scheme c).…”

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confidence: 99%

TfOH-promoted Classical Nazarov-type Cyclization of Benzofulvenes: Synthesis of Polycyclic 5H,10′H-spiro[benzo[k]phenanthridine-5,6′-dibenzopentalenes]

et al. 2021

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The reaction of o-benzofulvene with TfOH leads to intramolecular cyclization through novel C–C and C–N bond formation, resulting in the formation of 5H,10′H-spiro[benzo[k]phenanthridine-5,6′-dibenzopentalene]. This protocol provides a new molecular framework with reasonable to excellent yields and tolerates various electron-withdrawing/donating substituents. This method yields diastereoselectivity of up to >20:1. Furthermore, it is free of bases, oxidants, and metals and proceeds under mild reaction conditions, which are favorable for synthetic organic chemistry.

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“…[11] Die vorliegende Arbeit beschäftigt sich daher mit dieser und ähnlichen Reaktionen, die Benzopentafulvene durch regioselektive, elektrophile Cyclisierungen liefern. [6,7,12] Überraschenderweise liegen keine vollständigen spektroskopischen Daten zu Dibromstilben (7) vor. Eine Quelle gibt ein 1 H-NMR-Spektrum für (E)-7 an, dessen Konfiguration durch eine Kristallstrukturanalyse bestätigt wurde, [13] und an anderer Stelle wird über die Verschiebungen von 13 C-NMR-Signalen für (E)-7 [14] berichtet, die wir hingegen (Z)-7 zuordnen.…”

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