Metal organic reagents

Undoubtedly, the most widely used method for the synthesis of o.p. sulfoxides is the nucleophilic addition of metal organic reagent to an electrophilic sulfur with preestablished chirality, and the subsequent displacement of the sulfoxide. The reason is that either a good kinetic resolution of the sulfinyl chloride, generated first, or high separation factor of the intermediate diastereoisomers formed, permits the sulfinylating agent to be obtained in 100% de. 

A Michael addition of thiophenol to an a, j6-unsaturated carbonyl compound, followed by sodium borohydride reduction or addition of a metal-organic reagent, gives a y-phenylthioalcohol electrochemical reduction in dry DMF of the methanesulfonate of this alcohol yields a cyclopropane and a small amount of alkene [81] ... 

Since the first chemical experiments of Hofmann with ergot alkaloids in the 1930s and the first total synthesis of lysergic acid (133) by Kornfeld and Woodward in 1956 137), ergot alkaloids have attracted interest from the chemical synthesis community. In this chapter, synthetic approaches within the last two decades are presented, wherein attention is focused on syntheses using the application of modem catalytic methods and metal-organic reagents. Within the body of... 

Reactions. Phosgene interacts with many classes of inorganic and organic reagents. The reactions have been described extensively (10). Reaction with sodium metal takes place at room temperature, but reaction with 2inc requires warming. 

Organometalhcs. Halosilanes undergo substitution reactions with alkali metal organics, Grignard reagents, and alkylaluininums. These reactions lead to carbon—siUcon bond formation. 

The organic reagents are used extensively for determinations series of elements by different methods of analysis. We carry out the systematical investigation of organic derivatives of hydrazine as a reagent for determinations ion of metals by photometric and extractive-photometric methods or analysis, as well as methods of atomic absorption spectrometry. Series procedure determinations ion of metals in technical and environmental objects have been developed. 

These organic reagents were found effective for selective and group concentrate ion of metals, for sorption-photometry determinations ion of metals and for separation of metals. The high selectivity by concentrations ion of metals reach regulation pH solutions and selections replaces (R-) in the reagents type HI. 

Development of extraction-free photometric procedures for the determination of traces of metals for which hygienic and environmental regulations have been established is an urgent problem. For solution of this problem we used as an organic reagent l-(2- pyridylazo)-naphtol-2 (PAN) which forms intensely coloured complex compounds with many metals and is frequently used for their extraction-photometric determination however these procedures did not find wide application in water analysis due to lack of selectivity and necessity of using organic solvents. 

The regularity of micellar extraction of large grope of organic reagents and their complexes with metal ions was investigated. 

The literature on catalytic hydrogenation is very extensive, and it is tempting to think that after all this effort there must now exist some sort of cosmic concept that would allow one to select an appropriate catalyst from fundamentals or from detailed knowledge of catalyst functioning. For the synthetic chemist, this approach to catalyst selection bears little fruit. A more reliable, quick, and useful approach to catalyst selection is to treat the catalyst simply as if it were an organic reagent showing characteristic properties in its catalytic behavior toward each functionality. For this purpose, the catalyst is considered to be only the primary catalytic metal present. Support and... 

Anon, Organic Reagents for Metals and for Certain Radicals, Vol. II, Hopkin and Williams, London, 1964... 

Organic Reagents for Metals and other Reagent Monographs, Vol. 1, 5th edn, 1955. Hopkin Williams. 

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. 

Vol. 3 Photometric Determination of Traces of Metals. Fourth Edition Part I General Aspects. By E. B. Sandell and Hiroshi Onishi Part IIA Individual Metals, Aluminum to Lithium. By Hiroshi Onishi Part IIB Individual Metals, Magnesium to Zirconium. By Hiroshi Onishi Vol. 4 Organic Reagents Used in Gravimetric and Volumetric Analysis. By John F. Flagg (out ofprint)... 

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