Organic compounds, metal-catalyzed

Some nitric acid is used for the manufacture of explosives and chemicals, but much is converted on-site to the potentially explosive high nitrogen fertilizer ammonium nitrate (Section 2.11). Ammonia gas from the Haber plant is absorbed in aqueous HN03, and the NH4N03 solution is evaporated to a liquid melt (< 8% H20) for crystallization, but care must be taken to keep the pH of the solution above about 4.5 and to exclude any material (chlorides, organic compounds, metals) that might catalyze the explosive decomposition of NH4N03. It is also wise to keep the melt mass low and to vent it to avoid pressure buildup. The solid product should be stored well away from the main plant. 

Suzuki, A. Cross-coupling reactions of organoboron compounds with organic halides. Metal-Catalyzed Cross-Coupling Reactions 1998,49-97. 

The dimerization of aromatic isocyanates to form diazetidinediones 6, catalyzed by triethylphosphine, was already observed by Hofmann in I860 . Other trialkylphosphines, aryldialkylphosphines, hexaalkylphosphorous triamides, as well as tertiary amines, such as pyridine, dimethylimidazole and At,At,At, At -tetramethylguanidine and some metal organic compounds, also catalyze the dimerization of aromatic isocyanates. Some of the aromatic isocyanate dimers are listed in Table 3.2. 

In electroless deposition, the substrate, prepared in the same manner as in electroplating (qv), is immersed in a solution containing the desired film components (see Electroless plating). The solutions generally used contain soluble nickel salts, hypophosphite, and organic compounds, and plating occurs by a spontaneous reduction of the metal ions by the hypophosphite at the substrate surface, which is presumed to catalyze the oxidation—reduction reaction. 

R. A. Sheldon and J. K. Kochi in Metal-Catalyzed Oxidations of Organic Compounds, Academic Press, New York, 1981, p. 392. 

For a review of reactions of H2O2 and metal ions with all kinds of organic compounds, including aromatic rings, see Sosnovsky, G. Rawlinson, D.J. in Swem Organic Peroxides, vol. 2 Wiley NY, 1970, p. 269. See also Sheldon, R.A. Kochi, J.K. Metal-Catalyzed Oxidations of Organic Compounds, Academic Press NY, 1981. 

Maas, G. Transition-metal Catalyzed Decomposition of Aliphatic Diazo Compounds — New Results and Applications in Organic Synthesis, 137, 75-253 (1986). 

Pioneering work involving the combinahon of an organosulfide, a C-C unsaturated organic compound and a transihon metal catalyst was reported by Reppe in 1953, in which Ni(CO)4-catalyzed hydrothiocarboxylahori of alkyne or ethylene by thiol and CO was briefly described to give the corresponding thioesters 1 or 2 (an application of one of the so-called Reppe reachons) (Eqs. 7.1 and 7.2) [12, 13]. 

Although these reactions indicated the great potenhal of transihon metal-catalyzed reachons of organosulfides with C-C unsaturated organic compounds, little attenhon has been paid to such a combination of reactions for many years since then. In 1960, Holmquist and Carnaham reported the Co-catalyzed reachon of thiol with CO (1000 atm) at 250-300°C to afford thioester 3 in up to 46% yield with ca. 1-5 wt% of catalyst (Eq. 7.3) [14]. 

Although the path (a) has been verified by a stoichiometric reaction [23], the details of exact reaction mechanism remain unsettled. Triggered by this publication [and the Pd-catalyzed doublethiolation of alkynes described in Eq. (7.7) in Section 7-3], a number of transition metal-catalyzed additions of S-X or Se-X bonds to C-C unsaturated organic compounds started to be published. In 1994, BackvaU et al. applied the Pd(OAc)2-catalyzed hydrothiolation to conjugated enynes and obtained 17,... 

Although the selectivity of the reaction was unsatisfactory, this is, to my knowledge, the first documentation describing the transition metal catalyzed doublethio-latiorf of C-C unsaturated organic compounds. 

Most of the synthetic applications of organomercury compounds are in transition metal-catalyzed processes in which the organic substituent is transferred from mercury to the transition metal in the course of the reaction. Examples of this type of reaction... 

The oxidative cleavage of C=C bond is a common type of reaction encountered in organic synthesis and has played a historical role in the structural elucidation of organic compounds. There are two main conventional methods to oxidatively cleave a C=C bond (1) via ozonol-ysis and (2) via oxidation with high-valent transition-metal oxidizing reagents. A more recent method developed is via the osmium oxide catalyzed periodate oxidative cleavage of alkenes. All these methods can occur under aqueous conditions. 

In the presence of transition-metal complexes, organic compounds that are unsaturated or strained often rearrange themselves. One synthetically useful transition-metal catalyzed isomerization is the olefin migration reaction. Two general mechanisms have been proposed for olefin migrations, depending on the type of catalyst employed (A and B) (Scheme 3.8).137... 

Organic halides play a fundamental role in organic chemistry. These compounds are important precursors for carbocations, carbanions, radicals, and carbenes and thus serve as an important platform for organic functional group transformations. Many classical reactions involve the reactions of organic halides. Examples of these reactions include the nucleophilic substitution reactions, elimination reactions, Grignard-type reactions, various transition-metal catalyzed coupling reactions, carbene-related cyclopropanations reactions, and radical cyclization reactions. All these reactions can be carried out in aqueous media. 

Sheldon RA, Kochi JK (1981) Metal-catalyzed oxidations of organic compounds. Academic, New York... 

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