- Regioselective annulation of unsymmetrical 1,2-phenylenebis(diaryl/diheteroarylmethanol): A facile synthesis of anthracene, tetracene, and naphtho[b]thiophene analogues
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A systematic study on the regioselective cyclization of benzene- and naphthalene-based unsymmetrical diols with HBr (33 %) in acetic acid at room temperature led to the formation of annulation products. By using this method, synthesis of a wide variety of anthracene, tetracene and naphtho[b]thiophene analogues was achieved in good to excellent yields. By employing HBr (33 %) in acetic acid as a catalyst for regioselective cyclization of unsymmetrical diols was very facile and devoid of commonly encountered dihydroisobenzofuran formation. Regioselective cyclization of benzene- and naphthalene-based unsymmetrical diols with HBr (33 %) in acetic acid at room temperature led to the formation of annulated arenes and heteroarenes in good to excellent yields.
- Sivasakthikumaran, Ramakrishnan,Rafiq, Settu Muhammad,Sankar, Elumalai,Clement, J. Arul,Mohanakrishnan, Arasambattu K.
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p. 7816 - 7835
(2015/12/31)
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- Organocatalytic approach for C(sp3)-H bond arylation, alkylation, and amidation of isochromans under facile conditions
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A new catalytic approach for the synthesis of isochroman derivatives via direct C(sp3)-H bond arylation is described. The oxidation reaction with [bis(trifluoroacetoxy)iodo]benzene facilitates the regeneration of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in the C(sp3)-H bond arylation of isochroman. The reaction conditions can also be used for alkyl Grignard reagents and amides to afford the corresponding isochroman derivatives.
- Muramatsu, Wataru,Nakano, Kimihiro
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supporting information
p. 2042 - 2045
(2014/05/06)
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- Improved synthesis of aryl-substituted anthracenes and heteroacenes
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(Chemical Equation Presented) A Bronsted acid-catalyzed highly efficient construction of substituted arylanthracenes and heteroacenes is described, which is assumed to be initiated through the facile formation of a benzylic cation intermediate. This method offers several advantages in comparison with known aromatic cyclodehydration reactions such as high selectivities, mild reaction conditions, and easily accessible starting materials.
- Li, Guijie,Zhou, Shaolin,Su, Guowei,Liu, Yuanhong,Wang, Peng George
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p. 9830 - 9833
(2008/03/28)
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- Reductive Metalation of 1,3-Diphenylisobenzofuran. Stereoselective Formation of Cis Products
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1,3-Diphenylisobenzofuran was reduced in tetrahydrofuran by alkali metals to a dianion.This dianion on protonation, methylation, or carboxylation gave products which were predominantly cis.It is suggested that the dianion or the intermediate monoreacted monoanion adopts a preferred conformation in which steric interaction between the phenyl substituents is minimized and orbital overlap between the carbanion and the benzene ring is maximized.By use of this stereoselectivity of the dianion, a series of 1,3-polymethylene-bridged 1,3-diphenylphthalans was prepared.The possibility of single electron transfer during the alkylation of the dianion was examined by alkylating the dianion with tert-butyl halides.Complex reaction mixtures were formed but extensive alkylation occurred and mono- and dialkylation products were characterized.
- Smith, James G.,McCall, Robert B.
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p. 3982 - 3986
(2007/10/02)
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