- Template-Assisted Benzannulation Route to Pentacene and Tetracene Derivatives and its Application to Construct Amphiphilic Acenes That Self-Assemble into Helical Wires
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Pentacene is one of the most versatile organic semiconductors. New synthetic strategies to construct the pentacene skeleton are imperative to produce pentacene derivatives with appropriate solubility, stability, and optoelectronic properties for various applications. This paper describes a template-directed approach to pentacene derivatives. In the retrosynthesis, the acene skeleton is viewed as a laddered double strand polyene instead of the more intuitive linearly fused hexagons. Based on this vision, the template strand of polyene is constructed with Wittig olefination, whereas the second strand is accomplished with Knoevenagel condensation to produce pentacene and tetracene derivatives. The synthetic scheme is flexible enough to generate an array of acene derivatives with substitution patterns that were hitherto difficult to access. Amphiphilic pentacene and tetracene derivatives were also synthesized by the template strategy. One pentacene based amphiphilic rod-coil molecule undergoes self-assembly to form helical wire structures that were visualized with TEM.
- Pal, Bikash,Chang, Chun-Hsiung,Zeng, Cian-Jhe,Lin, Chih-Hsiu
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- A highly regio- and stereoselective cascade annulation of enals and benzodi(enone)s catalyzed by N-heterocyclic carbenes
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Three stereogenic centers in a row: The unconventional activation of enal compounds mediated by an N-heterocyclic carbene (NHC) has generated three consecutive reactive carbon centers that undergo highly regio- and stereoselective annulations with di(enone)s to generate benzotricyclic products containing multiple stereogenic centers (see scheme).
- Fang, Xinqiang,Jiang, Kun,Xing, Chong,Hao, Lin,Chi, Yonggui Robin
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supporting information; experimental part
p. 1910 - 1913
(2011/04/16)
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- Synthesis of spiro bis-indanes via domino Stetter-aldol-Michael and Stetter-aldol-aldol reactions: Scope and limitations
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The synthesis of spiro bis-indanes by means of N-heterocyclic carbene (NHC) catalysis is reported. The dimerization of various o-formylchalcone substrates or their combination with phthaldialdehyde derivatives under the catalysis of thiazolium-derived carbenes afforded Stetter-aldol-Michael products and Stetter-aldol-aldol products, respectively. The use of poor Michael acceptors in conjunction with an N-alkyltriazolium-derived catalyst furnished a variety of dibenzo[8]annulene products. This work highlights the interplay of a variety of factors affecting competing pathways in NHC-catalyzed domino reactions. Georg Thieme Verlag Stuttgart - New York.
- Sanchez-Larios, Eduardo,Holmes, Janice M.,Daschner, Crystal L.,Gravel, Michel
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supporting information; experimental part
p. 1896 - 1904
(2011/08/07)
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- First asymmetric synthesis of (Un)saturated 1-Alkylbenzo[c]azepin-3-ones: Extension to the corresponding benzazeplnes
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A flexible route for the stereoselective synthesis of a variety of structurally diverse (1R)-1-alkyldihydro and tetrahydro-benzazepin(ones) has been developed. The key step is a highly diastereoselective 1,2-addition process applied to a stereopure aromatic hydrazone combined with a ring-closing metathesis reaction to secure the formation of the seven-membered azaheterocycle ring system.
- Dumoulin, David,Lebrun, Stepfaane,Deniau, Eric,Couture, Axel,Grandclaudon, Pierre
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experimental part
p. 3741 - 3752
(2009/12/05)
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- Domino synthesis of bridged bicyclic tetrahydro-1,2-oxazines: Access to stereodefined 4-aminocyclohexanols
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Image Presented The intramolecular variant of the homo-[3 + 2]-dipolar cycloaddition of nitrones (generated in situ from an aldehyde and a hydroxylamine) with donor-acceptor cyclopropanes allows for the efficient synthesis of bridged tetrahydro-1,2-oxazines. This domino sequence produces adducts amenable to reductive N-O bond cleavage producing cis-1,4- aminocyclohexanols in excellent yields.
- Dias, Dwayne A.,Kerr, Michael A.
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supporting information; experimental part
p. 3694 - 3697
(2011/03/18)
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- Application of the intramolecular isomerisation - Aldolisation from allylic alcohols and allylic silyl ethers to the synthesis of indanones and indenones
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A new access to indanones was discovered through a one-step nickel or iron-mediated transposition of 2-hydroxyisobenzofurans. Starting from the corresponding silylenol ethers, a new one-pot tandem isomerisation-Mukaiyama aldol process was also developed. These versatile strategies will be useful for the preparation of various types of indanones and indenones.
- Petrignet, Julien,Roisnel, Thierry,Gree, Rene
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p. 7374 - 7384
(2008/03/14)
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- Asymmetric synthesis of thymine nucleoside analogues based on the isochroman core
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Diastereoisomeric analogues of d4T having an isochroman core as the glycone moiety have been prepared in seven steps. Starting from phthalaldehyde, two chiral centres analogous to the α/β anomers of D/L sugars were created. The first was obtained enantiom
- Len, Christophe,Violeau, Bruno
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p. 4835 - 4838
(2007/10/03)
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- Enantiomerical excess determination, purification and biological evaluation of (3S) and (3R) α,β-butenolide analogues of isobenzofuranone
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The asymmetric synthesis of isobenzofurane analogues, new potential antiviral agents, is reported. High performance liquid chromatography (HPLC) was the technique chosen to separate the enantiomers. We describe this chiral separation and then determine th
- Lipka, Emmanuelle,Vaccher, Marie-Pierre,Vaccher, Claude,Len, Christophe
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p. 501 - 504
(2007/10/03)
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- 1,3-Dihydrobenzo[c]furan nucleoside analogues: Additional studies of the thymine derivative
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The detailed study of the 1,3-dihydrobenzo[c]furan derivative of thymine is reported. The lack of anti-HIV activity of this compound in cell culture experiments is shown to be related to the inability of the corresponding 5′-triphosphate derivative to int
- Egron, David,Perigaud, Christian,Gosselin, Gilles,Aubertin, Anne-Marie,Faraj, Abdesslem,Selouane, Majid,Postel, Denis,Len, Christophe
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p. 4473 - 4475
(2007/10/03)
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- Enantiomeric d4T analogues and their structural determination
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Asymmetric synthesis of d4T analogues having a benzo[c]furan moiety with two asymmetric carbon atoms was realized using Sharpless asymmetric dihydroxylation as the key step in a synthesis starting from o-phthalaldehyde. Enantiomeric purities were determin
- Selouane, Abdelmajid,Vaccher, Claude,Villa, Pierre,Postel, Denis,Len, Christophe
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p. 407 - 413
(2007/10/03)
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- Simple and stereoselective syntheses of nucleoside analogues with a benzo[c]furan glycone moiety
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A series of d4T analogues have been synthesised in which the 2',3'- didehydro-2',3'-dideoxyribose moiety is replaced by a benzo[c]furan core. A simple strategy has been developed to access a range of compounds for biological screening. In addition, a ster
- Ewing, David F.,Fahmi, NourEddine,Mackenzie, Grahame,Pranzo, Alessandra
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p. 559 - 563
(2007/10/03)
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- Nucleoside analogues with a novel glycone based on the benzo[c]furan core
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Routes to novel nucleoside analogues based on 1,3-dihydrobenzo[c]furan have been investigated. Thus 1-(1,3-dihydro-3-hydroxymethylbenzo[c]furan-1- yl)-thymine, an analogue of d4T, was obtained as two diastereoisomers. The cis compound (quasi β-D/α-L stereochemistry) was obtained pure but the trans compound was only 90% pure. A purine analogue with a four atom spacer group between base and glycone was also prepared. The conformation of these constrained nucleosides was studied by molecular modelling.
- Ewing, David F.,Fahmi, Nour-Eddine,Len, Christophe,Mackenzie, Grahame,Ronco, Gino,Villa, Pierre,Shaw, Gordon
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p. 2613 - 2630
(2007/10/03)
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- Synthesis of New Five-Atom-Linked Capped Porphyrins
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The synthesis and characterization of three new five-atom-linked "capped" porphyrins, 6, 12, and 18, are reported.The general synthetic procedure involves synthesis of a tetraaldehyde "cap" by reacting the five-atom "arm" with 1,2,4,5-tetrahydroxybenzene
- Ma, Wuping,Slebodnick, Carla,Ibers, James A.
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p. 6349 - 6353
(2007/10/02)
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- THE SYNTHESIS OF A PORPHYRIN WITH A HYDROCARBON ENCAPSULATED FACE
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The uniquely hydrocarbon-like capped porphyrin (C70H68N4), 1i, has been successfully prepared by a high dilution reaction of pyrrole with tetrakis-1,2,4,5--benzene 1h in the presence of boron trifluoride etherate.The aldehyde
- Schnatter, Wayne F. K.,Almarsson, Oern,Bruice, Thomas C.
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p. 8687 - 8700
(2007/10/02)
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