- Isoacenofuran: A novel quinoidal building block for efficient access to high-ordered polyacene derivatives
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Herein, a simple and practical method for generating isoacenofuran, a new π-extended quinoidal building block, was developed. A three-step protocol involving double nucleophilic additions of alkynyllithiums to acene-2,3-dicarbaldehyde, mono-oxidation, and acid-promoted cyclization enables the generation of the target molecule, which is trapped by a dienophile to produce highly condensed acenequinones. Further transformations by double nucleophilic additions of alkynyllithium to hexacenequinone, followed by reductive aromatization, produce tetraalkynylhexacenes with a remarkably higher stability than that of the previously reported substituted hexacenes.
- Kitamura, Kei,Kudo, Ryoji,Sugiyama, Haruki,Uekusa, Hidehiro,Hamura, Toshiyuki
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supporting information
p. 14988 - 14991
(2020/12/23)
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- Phosphine-Mediated Iterative Arene Homologation Using Allenes
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A PPh3-mediated multicomponent reaction between o-phthalaldehydes, nucleophiles, and monosubstituted allenes furnishes functionalized non-C2-symmetric naphthalenes in synthetically useful yields. When the o-phthalaldehydes were reacted with 1,3-disubstituted allenes in the presence of PPh2Et, naphthalene derivatives were also obtained in up to quantitative yields. The mechanism of the latter transformation is straightforward: aldol addition followed by Wittig olefination and dehydration. The mechanism of the former is a tandem γ-umpolung/aldol/Wittig/dehydration process, as established by preparation of putative reaction intermediates and mass spectrometric analysis. This transformation can be applied iteratively to prepare anthracenes and tetracenes using carboxylic acids as pronucleophiles.
- Zhang, Kui,Cai, Lingchao,Jiang, Xing,Garcia-Garibay, Miguel A.,Kwon, Ohyun
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p. 11258 - 11261
(2015/09/21)
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- Iterative synthesis of acenes via homo-elongation
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Starting from aromatic ortho-dialdehydes, we devised a homo-elongation protocol that combines a Wittig olefination and subsequent intramolecular Knoevenagel condensation to produce acene diesters and dinitriles. The Royal Society of Chemistry.
- Lin, Chih-Hsiu,Lin, Ke-Han,Pal, Bikash,Tsou, Li-Der
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supporting information; experimental part
p. 803 - 805
(2009/07/10)
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- First-order hyperpolarizability of oligo-acene derivatives by hyper-Rayleigh scattering
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First-order hyperpolarizabilities β for a series of oligo-acene derivatives were estimated as a function of the conjugation length by means of the hyper-Rayleigh scattering (HRS) technique. Satisfactory data acquisition and analyses gave the hyperpolarizabilities (17 ± 2) × 10-30 and (68 ± 8) × 10-30 esu for naphthalene-2,3-dialdehyde and anthracene-2,3-dialdehyde, respectively. The pure β value of tetracene-2,3-dialdehyde (OA4) could not be determined because of multiphoton absorption induced fluorescence superimposed on the HRS signal. A large β value (≈ 180 × 10-30 esu) is expected for OA4 by extrapolating the conjugation length dependence on β.
- Ishibashi, Kenichi,Iyoda, Tomokazu,Hashimoto, Kazuhito,Fujishima, Akira,Shirai, Yasuo,Jiro, Abe
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p. 107 - 111
(2007/10/03)
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