- Syntheses of extreme sterically hindered 4-methoxyboronic acids
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4-Iodoanisoles 3a,b, 3d and 4-bromoanisoles 4a-d were readily obtained. An extreme steric hindrance precluded obtaining 3c. Catalytic borylation of 3a,b, 3d followed by hydrolysis of boronic ester 26a,b, 26d easily provided the boronic acids 5a,b, 5d. Com
- Diemer, Vincent,Chaumeil, Hélène,Defoin, Albert,Carré, Christiane
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scheme or table
p. 918 - 929
(2010/03/25)
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- Syntheses of sterically hindered pyridinium phenoxides as model compounds in nonlinear optics
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Noncentrosymmetric molecules with a π-conjugated system and, among them, push-pull molecules such as pyridinium phenoxide, are a promising new class of materials for applications in optoelectronics due to their nonlinear optical (NLO) properties. Modelling studies have indicated that an increase in the twist angle between the two aromatic rings leads to an enhancement of the NLO properties. In order to confirm this feature experimentally, it was necessary to prepare a series of new hindered pyridinium phenoxides. Their efficient syntheses by Suzuki cross-coupling reactions are described herein. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Diemer, Vincent,Chaumeil, Helene,Defoin, Albert,Fort, Alain,Boeglin, Alex,Carre, Christiane
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p. 2727 - 2738
(2007/10/03)
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- Effect of ligand structure on the zinc-catalyzed Henry reaction. Asymmetric syntheses of (-)-denopamine and (-)-arbutamine
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(Matrix presented) Syntheses of variously modified ligands for the dinuclear zinc catalysts for the asymmetric aldol and nitroaldol (Henry) reactions are reported. Catalytic enantioselective nitroaldol reactions promoted by these modified ligands led to efficient syntheses of the β-preceptor agonists (-)-denopamine and (-)-arbutamine.
- Trost, Barry M.,Yeh, Vince S. C.,Ito, Hisanako,Bremeyer, Nadine
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p. 2621 - 2623
(2007/10/03)
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- Synthesis of Chiral C2-Symmetric Binucleating Ligands
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The synthesis of a series of chiral enantiomerically pure C2-symmetric binucleating ligands is reported. Ligands of type 1-4, which consist of a phenolic or heterocyclic unit bridging two chiral dihydrooxazole rings, are readily accessible from
- Fahrni, Christoph J.,Pfaltz, Andreas
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p. 491 - 506
(2007/10/03)
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- A New Aromatic Annelation Reaction with Two Synthons, Enaminones and 3-Oxoglutarate. Studies on the β-Carbonyl Compounds Connected with β-Polyketides. VIII
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Reactions of the enaminones 1 with dimethyl 3-oxoglutarate in the presence of KF-AcOH or AcONa-AcOH and 18-crown-6 gave the dimethyl 2-hydroxy-1,3-benzenedicarboxylates 3, providing a new aromatic annelation reaction.Keywords - enaminone; dimethyl 3-oxoglutarate; buffer catalysis; aromatic annelation; dimethyl 2-hydroxy-1,3-benzenedicarboxylate
- Takeuchi, Naoki,Okada, Naomi,Tobinaga, Seisho
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p. 4355 - 4359
(2007/10/02)
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