Intramolecular oxidative diamination and aminohydroxylation of olefins under metal-free conditions

A metal-free procedure that is simple to operate and convenient to handle was developed for the facile intramolecular oxidative diamination of olefins using an iodobenzene diacetate oxidant and a halide additive to furnish bisindolines at room temperature. The present reaction is featured by mild conditions, a broad substrate scope, and excellent functional group tolerance. The same protocol was successfully extended to the aminohydroxylation.     

Three characteristic reactions of organocobalt compounds in organic synthesis

Organocobalt compounds in organic synthesis have three characteristic reactions. The first occurs because cobalt has a high affinity to carbon–carbon π‐bonds or carbon–nitrogen π‐bonds. The second occurs because cobalt has a high affinity to carbonyl groups. The third is due to cobalt easily tending to form square‐planar bipyramidal six‐coordination structures with four nitrogen atoms or two nitrogen atoms and two oxygen atoms at the square‐planar position, and to bond with one or two carbon atoms at the axial position. The first characteristic reactions are the representative reactions of organocobalt compounds with a mutually bridged bond between the two π‐bonds of acetylene and the cobalt–cobalt bond of hexacarbonyldicobalt. These are reactions with a Co₂(CO)₆ protecting group to reactive acetylene bond, the Nicholas reactions, the Pauson–Khand reactions ([2 + 2 + 1] cyclizations), [2 + 2 + 2] cyclizations, etc. These reactions are applied for the syntheses of many kinds of pharmaceutically useful compounds. The second reactions are carbonylations that have been used or developed as industrial processes such as hydroformylation for the manufacture of isononylaldehyde, and carbonylation for the production of phenylacetic acid from benzyl chloride. The third reactions are those reactions with the B₁₂‐type catalysts, and they have recently been used in organic syntheses and are utilized as catalysts for stereoselective syntheses. These reactions have been used as new applications for organic syntheses. Copyright © 2007 John Wiley & Sons, Ltd.     

Applications of bismuth(III) compounds in organic synthesis

This review article summarizes the applications of bismuth(III) compounds in organic synthesis since 2002. Although there are an increasing number of reports on applications of bismuth(III) salts in polymerization reactions, and their importance is acknowledged, they are not included in this review. This review is largely organized by the reaction type although some reactions can clearly be placed in multiple sections. While every effort has been made to include all relevant reports in this field, any omission is inadvertent and we apologize in advance for the same (358 references).     

Road maps for nitrogen-transfer catalysis: the challenge of the osmium(VIII)-catalyzed diamination

Although the Sharpless dihydroxylation has been used on laboratory and industrial scales for several decades, an analogous osmium-catalyzed diamination is unknown. To explore the reaction of osmium(VIII) oxo-imido complexes with C=C bonds, density functional calculations have been performed. The calculations predict a chemoselective and perispecific [3+2] addition of the NH=Os=NH moiety of diimidodioxoosmium(VIII) to ethylene, yielding dioxoosma-2,5-diazolidine. At first sight, this metallacycle seems extremely stable; it is more stable than diimidoosma-2,5-dioxolane by 40 kcal mol(-1). However, a comparison of the thermodynamic reaction profiles for catalytic model cycles of dihydroxylation, aminohydroxylation, and diamination reveals that, contrary to common belief, the instability of the metal=N bond in the osmium(VIII) imido complex rather than the stability of the metal-N bond in the osmium(VI) intermediate causes most of the energy difference between the metallacycles. Substituents on the substrate have a small effect on the thermodynamic reaction profiles, whereas substituents on the imido ligands allow steric and electronic control of the reaction free enthalpies in the range of up to 25 kcal mol(-1). The results of this study help identify potential challenges in the development of the as-yet hypothetical title reaction and provide a modular concept for exploring novel catalytic routes.     

Three characteristic reactions of alkynes with metal compounds in organic synthesis

Alkynes have two sets of mutually orthogonal π‐bonds that are different from the π‐bonds of alkenes. These π‐bonds are able to bond with transition metal compounds. Alkynes easily bond with the various kinds of compounds having a π‐bond such as carbon monoxide, alkenes, other alkynes and nitriles in the presence of the transition metal compounds. The most representative reaction of alkynes is called the Pauson–Khand reaction. The Pauson–Khand reactions include the cyclization of alkynes with alkenes and carbon monoxide in the presence of cobalt carbonyls. Similar Pauson–Khand reactions also proceed in the presence of other transition metal compounds. These reactions are the first type of characteristic reaction of alkynes. Other various kinds of cyclizations with alkynes also proceed in the presence of the transition metal compounds. These reactions are the second type of characteristic reaction of alkynes. These include cyclooligomerizations and cycloadditions. The cyclooligomerizations include mainly cyclotrimerizations and cyclotetramerizations, and the cycloadditions are [2 + 2], [2 + 2 + 1], [2 + 2 + 2], [3 + 2], [4 + 2], etc., type cycloadditions. Alkynes are fairly reactive because of the high s character of their σ‐bonds. Therefore, simple coupling reactions with alkynes also proceed besides the cyclizations. The coupling reactions are the third type of characteristic reactions of alkynes in the presence of, mainly, the transition metal compounds. These reactions include carbonylations, dioxycarbonylations, Sonogashira reactions, coupling reactions with aldehydes, ketones, alkynes, alkenes and allyl compounds. Copyright © 2008 John Wiley & Sons, Ltd.     

Characteristic reactions of group 9 transition metal compounds in organic synthesis

Group 9 metal compounds in organic synthesis have two characteristic reactions. The first occurs because the group 9 metals have a high affinity to carbon–carbon or carbon–nitrogen π‐bonds. The first type of characteristic reactions in these group 9 metal compounds includes Pauson–Khand reactions, the Pauson–Khand‐type reactions ([2 + 2 + 1] cyclization), the other cyclizations and coupling reactions. The second occurs because the group 9 metals have a high affinity to carbonyl groups. The second type of characteristic reactions includes carbonylations such as hydroformylations, the carbonylations of methanol, amidocarbonylations and other carbonylations. The first characteristic reactions are applied for the synthesis of fine chemicals such as pharmaceuticals and agrochemicals. However, the second characteristic reactions are utilized not only for fine chemicals but also for important bulk commodity chemicals such as aldehydes, carboxylic acids and alcohols. Copyright © 2009 John Wiley & Sons, Ltd.     

Studies in the field of synthesis and reactions of unsaturated organic silicon compounds

Summary We have studied the reaction of tertiary -silicoacetylene alcohofs with concentrated hydrochloric acid and thionyl chloride and have suggested three methods for the synthesis of tertiary -silicoacetylene chlorides of the propargyl type.     

Three types of reactions with intramolecular five-membered ring compounds in organic synthesis

There are three types of reactions with intramolecular five-membered ring compounds in organic syntheses: The first type is reactions involving intramolecular five-membered ring compounds which are utilized for the ease of synthesis of these compounds and the stability of the products. The second is reactions performed via intramolecular five-membered ring intermediates, because such intermediates are very reactive and labile compounds. The third is the metal-catalyzed reactions with the intramolecular five-membered ring compounds because these metal compounds have catalytic activities. The third type reactions involving intramolecular five-membered ring pincer compounds are also provided.The first type reactions include carbonylations, alkenylations, alkynylations, acylations, isocyanations, Diels-Alder reactions, etc. The second type reactions include carbonylations, cross-coupling reactions, hydroacylations, ring expansion reactions, carbocyclizations, etc. The third type reactions include cross-coupling reactions, rearrangements, metatheses, reductions, Michael reactions, dehydrogenations, Diels-Alder reactions, etc.     

Organometallic compounds in organic synthesis: reactions of some tricarbonylcyclohexadienylium-iron complexes with trimethylislyl enol ethers

O-Silylated enolates derived from ketones react with tricarbonylcyclohexadienyl-iron cationic complexes under very mild conditions to form carbon-carbon bonds in excellent yields.     

Heterocyclic diazo compounds as starting materials in organic synthesis (review)

Data on the structures and reactions of heterocyclic diazo compounds that lead to the formation of new heterocyclic systems as a result of intra- or intermolecular cyclization and rearrangements are systematized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 579–603, May, 1980.     

Arylidene pyruvic acids (APAs) in the synthesis of organic compounds

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Organometallic compounds in organic synthesis : electrophilic reactions of some tricarbonylcyclohexadienylium-iron complexes with allyltrimethyl silanes.

Allyltrimethylsilanes react with a range of tricarbonylcyclohexadienyl-iron complexes under mild conditions to form new carbon-carbon bonds in excellent yields.     

Pd-N-heterocyclic carbene (NHC) organic silica: synthesis and application in carbon-carbon coupling reactions

The first Pd-N-heterocyclic carbene (NHC) complex in the form of organic silica was prepared using sol-gel method and its application in Heck and Suzuki reactions was demonstrated. These C-C coupling reactions proceeded efficiently under the influence of microwave irradiation, with excellent yield, without any change in catalytic activity for at least five reaction cycles, with negligible Pd concentration in the end product.