- Recent developments in the chemistry of heteroaromatic N -oxides
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Selected developments in the chemistry of heteroaromatic N-oxides since 2001 are presented in this review. The use of these N-oxides, both in late-transition-metal-catalyzed oxidations of carbon-carbon triple bonds and in regioselective C-H functionalizations of the heteroarene, are contemporary topics of interest and the focus of the discussion. 1 Introduction 2 Synthesis of Heteroaromatic N-Oxides 2.1 Direct Oxidation of Hindered Heteroarenes 2.2 Through Construction of Heteroaromatic Rings 3 Heteroaromatic N-Oxides as Oxidants 3.1 Alkyne Oxidation 3.2 Allene Oxidation 3.3 Carbene Oxidation 4 Heteroaromatic N-Oxides as Substrates 4.1 Deoxygenative ortho-C-H Functionalization with Prior Activation 4.2 Deoxygenative ortho-C-H Functionalization with Nonstabilized Carbanions 4.3 Nondeoxygenative C-H Functionalization 4.3.1 ortho-C-H Functionalization 4.3.2 N-Oxide Directed ortho-Alkyl C-H Functionalization 4.3.3 N-Oxide Directed Remote C-H Functionalization 4.4 1,3-Dipolar Cycloaddition 5 Conclusion and Outlook.
- Wang, Youliang,Zhang, Liming
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- Pd-catalyzed decarboxylative cross-coupling of 2-carboxyazine N-oxides with various (hetero)aryl halides
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Decarboxylative cross-coupling reactions of substituted 2-carboxyazine N-oxides, with a variety of (hetero)aryl halides, by bimetallic Pd 0/CuI and Pd0/AgI catalysis are reported. Two possible pathways, a conven
- Rouchet, Jean-Baptiste,Schneider, Cedric,Spitz, Cedric,Lefevre, Johan,Dupas, George,Fruit, Corinne,Hoarau, Christophe
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supporting information
p. 3610 - 3615
(2014/04/03)
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- Catalyst and base controlled site-selective sp2 and sp3 direct arylation of azine N-oxides
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Site-selective direct arylation of both sp2 and sp3 sites on azine N-oxide substrates is described. The arylation reactions are carried out in either a divergent manner or a sequential manner. The sp3 arylation reaction is applied to the synthesis of the natural products, papaverine and crykonisine, and a rationale for low reactivity of electron-deficient aryl halides is provided. Mechanistic investigations point toward the intimate involvement of the base in the mechanism of these reactions.
- Schipper, Derek J.,Campeau, Louis-Charles,Fagnou, Keith
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experimental part
p. 3155 - 3164
(2009/08/15)
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- Site-selective sp2 and benzylic sp3 palladium-catalyzed direct arylation
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Palladium-catalyzed site selective arylation reactions of both sp2 and benzylic sp3 sites on azine and diazine N-oxide substrates are described that occur in good to excellent yield and with complete selectivity for reaction at the desired position. These studies have uncovered the need to properly control the metal to ligand ratio in sp2 arylation and necessitated a complete reinvestigation of all reaction parameters for sp3 arylation. From these studies, the choice of base emerged as a pivotal component for site selectivity, pointing to its intimate involvement in the mechanism of direct arylation. These site selective reactions have been validated in both divergent and sequential derivatizations of heterocyclic compounds represent an attractive alternative to other routes to this class of molecule. Copyright
- Campeau, Louis-Charles,Schipper, Derek J.,Fagnou, Keith
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p. 3266 - 3267
(2008/10/09)
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- Heterocyclic derivatives in the treatment of Ischaemia and related diseases
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Compounds of the formula: STR1 wherein A, R1, R2, R3 and m are defined as in the specification or a pharmaceutically acceptable acid addition salt or N-oxide thereof, are calcium and sodium channel antagonists useful for treating mammals having a variety of disease states, such as stroke, epilepsy, hypertension, angina, migraine, arrhythmia, thrombosis, embolism, and also for treatment of spinal injuries.
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