Taeko Izumi

Bio: Taeko Izumi is an academic researcher from Yamagata University. The author has contributed to research in topics: Palladium & Ferrocene. The author has an hindex of 21, co-authored 172 publications receiving 1577 citations.

Synthesis of 3-Substituted Indoles by a Palladium-Assisted Reaction

Abstract: In the presence of palladium(II) chloride, 2-bromoanilines readily react with the methyl vinyl ketone and the ethyl acrylate to produce vinylogous arylamino ketones and esters. A palladium(0)-assisted cyclization of the arylamino ketones and the esters leads to a formation of 3-substituted indoles.

The σ-Bonded Palladium(II) Complex of 2-Pyridylferrocene

Abstract: 2-Pyridylferrocene reacts with lithium tetrachloropalladate(II) in the presence of sodium acetate to give an ortho-palladated binuclear complex (4). The σ-bonded structure of 4 was confirmed by studies of the IR and NMR spectra and of the reactions of 4 with thallium (I) acetylacetonate and lithium aluminum deuteride. The reactions of 4 with carbon monoxide, butyllithium, and bromine were also examined.

A New Method of Preparing Flavones

Abstract: The reaction of the sodium salt of 2′-hydroxychalcones with palladium(II) salt led to the formation of flavones, accompanied by a small amount of flavanones. The reaction proceeds via a phenoxypalladation, followed by the elimination of a hydridopalladium(II).

Arylation and Vinylation Reactions of Benzo[b]furan via Organopalladium Intermediates

Abstract: The Heck reaction of benzo[b]furan with arylpalladium chloride leads to the formation of 2-arylbenzo[b]-furan derivatives. In the presence of palladium acetate, benzo[b]furan reacts in benzene to give 2,2′-bibenzo[b]furyl, accompanied by 2-arylbenzo[b]furan. In the phenylation of [2-2H]benzo[b]furan with phenylpalladium salts, it was confirmed that no hydride shift takes place in the reaction. In the presence of palladium acetate, benzo[b]furan also reacts with olefin to produce benzo[b]furyl-substituted olefins, accompanied by a small amount of 2,2′-bibenzo[b]furyl, and from the reaction of [β,β-2H2]styrene and benzo[b]furan in the presence of palladium acetate it was confirmed that no hydride shift occurs in the reaction.

The heck reaction as a sharpening stone of palladium catalysis.

Abstract: s, or keywords if they used Heck-type chemistry in their syntheses, because it became one of basic tools of organic preparations, a natural way to

Aryl-aryl bond formation by transition-metal-catalyzed direct arylation.

Abstract: The biaryl structural motif is a predominant feature in many pharmaceutically relevant and biologically active compounds. As a result, for over a century 1 organic chemists have sought to develop new and more efficient aryl -aryl bond-forming methods. Although there exist a variety of routes for the construction of aryl -aryl bonds, arguably the most common method is through the use of transition-metalmediated reactions. 2-4 While earlier reports focused on the use of stoichiometric quantities of a transition metal to carry out the desired transformation, modern methods of transitionmetal-catalyzed aryl -aryl coupling have focused on the development of high-yielding reactions achieved with excellent selectivity and high functional group tolerance under mild reaction conditions. Typically, these reactions involve either the coupling of an aryl halide or pseudohalide with an organometallic reagent (Scheme 1), or the homocoupling of two aryl halides or two organometallic reagents. Although a number of improvements have developed the former process into an industrially very useful and attractive method for the construction of aryl -aryl bonds, the need still exists for more efficient routes whereby the same outcome is accomplished, but with reduced waste and in fewer steps. In particular, the obligation to use coupling partners that are both activated is wasteful since it necessitates the installation and then subsequent disposal of stoichiometric activating agents. Furthermore, preparation of preactivated aryl substrates often requires several steps, which in itself can be a time-consuming and economically inefficient process.

Synthesis and functionalization of indoles through palladium-catalyzed reactions

Abstract: The substituted indole nucleus [indole is the acronym from indigo (the natural dye) and oleum (used for the isolation)] is a structural component of a vast number of biologically active natural and unnatural compounds. The synthesis and functionalization of indoles has been the object of research for over 100 years, and a variety of well-established classical methods are now available, to name a few of them, the Fisher indole synthesis, the Gassman synthesis of indoles from N-halo-anilines, the Madelung cyclization of N-acyl-o-toluidines, the Bischler indole synthesis, the Batcho-Leimgruber synthesis of indoles from o-nitrotoluenes and dimethylformamide acetals, and the reductive cyclization of o-nitrobenzyl ketones.1 In the last 40 years or so, however, palladiumcatalyzed reactions, generally tolerant of a wide range of functionalities and therefore applicable to complex molecules, have achieved an important place in the arsenal of the practicing organic chemist. Since the invention of an industrial process for the palladium-catalyzed production of acetaldehyde from ethylene in the presence of PdCl2 and CuCl2, an everincreasing number of organic transformations have been based on palladium catalysis. Almost every area of the organic synthesis has been deeply influenced by the profound potential of this versatile transition metal, modifying the way organic chemists design and realize synthetic processes.2,3 Because of its catalytic nature, palladium-catalyzed synthesis can provide access to fine chemicals, agrochemical and pharmaceutical intermediates, and active ingredients in fewer steps and with less waste than classical † In memory of Prof. Bianca Rosa Pietroni, a colleague and very close friend. * To whom correspondence should be addressed. Phone: + 39 (06) 4991-2785. Fax: + 30 (06) 4991-2780. E-mail: sandro.cacchi@ uniroma1.it. 2873 Chem. Rev. 2005, 105, 2873−2920

Metal-Initiated Amination of Alkenes and Alkynes.

Abstract: The catalytic production of organic molecules is one of the most important applications of organometallic chemistry. For this purpose the distinct reaction chemistry of organic ligands covalently bound to transition metals is exploited. Most organometallic chemistry has focused on the formation of carboncarbon or carbon-hydrogen bonds. The platinum group metals, in particular Pd and Rh, have been the most commonly used elements insfrequently commercializedscatalytic processes that include hydrogenation, hydroformylation and others. On the other hand, carbon-oxygen and carbon-nitrogen bonds are found in the majority of organic molecules and are of particular importance in physiologically active substances. However, catalytic organometallic reactions that lead to the formation of carbonheteroatom bonds are less common.1,2 The catalytic construction of carbon-nitrogen bonds in amines is particularly rare.3-10 Clearly, efficient catalytic routes to nitrogen based molecules are of great interest.11 Especially useful are catalytic hydroaminations of olefins and alkynes which avoid production of byproducts, like salts, generally observed in metal-catalyzed aminations of C-X derivatives (X ) e.g., halogen). However, known aminations of olefins often require stoichiometric use of transition metals and general methods for carrying out aminations catalytically are not yet available.12,13 Most of the present enantioselective syntheses of molecules bearing an amine functionality use classical stoichiometric reactions with chiral auxiliaries or utilize enantiomerically pure starting material.14-16 Hydroamination of alkenes and alkynes, which constitutes the formal addition of a N-H bond across a carbon-carbon multiple bond (Scheme 1), is a transformation of seemingly fundamental simplicity and would appear to offer the most attractive route to numerous classes of organo-nitrogen molecules such as alkylated amines, enamines or imines. Organic chemists have developed various synthetic approaches for the amination of olefins.17-19 Direct addition of nucleophiles H-NR2 to activated alkenes is of general importance for the synthesis of compounds with nitrogen atoms â to groups such as keto, ester, nitrile, sulfoxide, or nitro.13,20-23 These additions usually lead to the anti-Markovnikov products. On the other hand aliphatic olefins as well as most aromatic olefins are often aminated to give the Markovnikov product. One possibility to reverse the reactivity of aliphatic olefins is the use of electrophilic nitrogen radicals which have been used to obtain anti-Markovnikov products.24 In the past much work has been done on the activation of alkenes with stoichiometric amounts of metal.24 Reactions are mostly promoted by complexes of titanium,25 iron,26 zirconium,27 palladium28-31 and mercury.32,33 However, catalytic additions of amines H-NR2 to nonactivated double or triple bonds are still rare. Two basic approaches have been employed to catalytically effect aminations and involve either alkene/alkyne or amine activation routes (Scheme 2).34,140 Alkene activation is generally accomplished with late-transition-metal catalysts, which render coordinated olefins more susceptible to attack by † Dedicated to Dipl. Chem. Martin Eichberger (deceased 11/20/ 1997). 675 Chem. Rev. 1998, 98, 675−703