Halides, alkyl, and

Complexes containing halide, alkyl, and aryl ligands 820... 

Ion exchangers have been produced from crosslinked xanthates, applied as either their sodium or magnesium salts.2176,2186-2193 Crosslinked xanthates are also used to make molded articles and films.2155 Reported crosslinkers include aldehydes, urea, isocyanantes, acids, acyl halides, alkyl and aryl halides, organosilyl halides,2194... 

The reagent reacts specifically with allylic and propargylic halides alkyl and benzylic halides are unreactive. 

Table II gives examples of several compounds of Os (II) showing that osmium in a formal oxidation state of +2 can bind N2 in the presence of a wide range of other hgands, NH3, NH3 + N2, halide, alkyl and aryl phosphines. In such compounds, the presence of other ligands that can accept d electrons from the metal reduces the extent of metal-to-hgand 7T electron transfer in the metal—N2 bond. This is indicated by an increase in the N2 stretching frequency, other things being equal. A further example is cw-[Os (NH3)4CO.N2] in which vn2 is raised to 2180 cm ...

The following metal compounds are used for the preparation of the catalysts oxides, metal carbonyls, halides, alkyl and allyl complexes, as well as molybdenum, tungsten, and rhenium sulfides. Oxides of iridium, osmium, ruthenium, rhodium, niobium, tantalum, lanthanum, tellurium, and tin are effective promoters, although their catalytic activity is considerably lower. Oxides of aluminum, silicon, titanium, manganese, zirconium as well as silicates and phosphates of these elements are utilized as supports. Also, mixtures of oxides are used. The best supports are those of alumina oxide and silica. 

Studies of the coordination compounds of boron, especially of its halides, alkyls and hydrides, have contributed substantially to our understanding of the factors which influence the stability of coordination compounds in general. The factors which particularly concern boron complexes are inductive and steric efi ects and reorganization energies, as explained below. 

Hydrides and halides Alkyl and aryl ligands Alkene, alkyne and allyl ligands... 

Alkyl and aryl-alkyl halides form 2-naphthyl ethers with 2-naphthol. 

Wurtz - Fittig reaction. The interaction of an aryl halide, alkyl hahde and sodium gives a reasonable yield of an alkyl aryl hydrocarbon, for example ... 

The products from a mixture of alkyl and aryl halides may be represented by the following scheme ... 

Other catalysts which may be used in the Friedel - Crafts alkylation reaction include ferric chloride, antimony pentachloride, zirconium tetrachloride, boron trifluoride, zinc chloride and hydrogen fluoride but these are generally not so effective in academic laboratories. The alkylating agents include alkyl halides, alcohols and olefines. 

The process whereby aldehydes are produced from arylmethyl (also alkyl and other) halides by the action of hexamine is known as the Sommelet reaction. The reaction is essentially the conversion of an amine into an aldehyde the hexamine serves the dual role of converting the halide into the amine and the amine into the aldehyde, but its function is different in the two steps. When starting from a halide, the reaction proceeds in three stages —... 

Alkyl halides and sulfonates are the most frequently used alkylating acceptor synthons. The carbonyl group is used as the classical a -synthon. O-Silylated hemithioacetals (T.H. Chan, 1976) and fomic acid orthoesters are examples for less common a -synthons. In most synthetic reactions carbon atoms with a partial positive charge (= positively polarized carbon) are involved. More reactive, "free carbocations as occurring in Friedel-Crafts type alkylations and acylations are of comparably limited synthetic value, because they tend to react non-selectively. 

The use of oximes as nucleophiles can be quite perplexing in view of the fact that nitrogen or oxygen may react. Alkylation of hydroxylamines can therefore be a very complex process which is largely dependent on the steric factors associated with the educts. Reproducible and predictable results are obtained in intramolecular reactions between oximes and electrophilic carbon atoms. Amides, halides, nitriles, and ketones have been used as electrophiles, and various heterocycles such as quinazoline N-oxide, benzodiayepines, and isoxazoles have been obtained in excellent yields under appropriate reaction conditions. 

Alkyl- and arylmercury(II) halides are used for the ketone formation[402]. When active methylene compounds. such as /f-keto esters or malonates are used instead of alcohols, acylated / -keto esters and malonates 546 are produced, For this reaction, dppf is a good ligand[403]. The intramolecular version of the reaction proceeds by trapping the acylpalladium intermediate with eno-late to give five- and six-membered rings smoothly. Formation of 547 by intramolecular trapping with malonate is an example[404]. 

Consider three compounds similar m size and shape the alkane propane the alkyl halide fluoroethane and the alcohol ethanol... 

Both reactants m the Williamson ether synthesis usually originate m alcohol pre cursors Sodium and potassium alkoxides are prepared by reaction of an alcohol with the appropriate metal and alkyl halides are most commonly made from alcohols by reaction with a hydrogen halide (Section 4 7) thionyl chloride (Section 4 13) or phosphorus tri bromide (Section 4 13) Alternatively alkyl p toluenesulfonates may be used m place of alkyl halides alkyl p toluenesulfonates are also prepared from alcohols as their imme diate precursors (Section 8 14)... 

The reaction is of the 8 2 type and works best with primary and secondary alkyl halides Elimination is the only reaction observed with tertiary alkyl halides Aryl and vinyl halides do not react Dimethyl sulfoxide is the preferred solvent for this reaction but alcohols and water-alcohol mixtures have also been used... 

Na2S04 Ketones, acids, alkyl and aryl halides 12 1.25 150... 

Alkyl and arylboranes are obtained (35) from BF using the appropriate Grignard reagent, alkylalurninum halide, or zinc alkyl, using diethyl ether as the solvent (see also Organometallics) ... 

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