Grignard compounds hydrocarbons

The weak chemiluminescence of Grignard compounds in air has been known since 1906. A radical chain mechanism similar to that of hydrocarbon autoxidation appears to provide the excitation energy of the emitting product. Until recently the relations between constitution and chemiluminescence in Grignard compounds were rather obscure j>-chloro-phenylmagnesium chloride was found to be the most efficient compound. 

Grignard). (B., 39, 634.)—When a Grignard compound is treated with water or other substance containing a hydroxyl group hydrolysis occurs, and the corresponding hydrocarbon is obtained. 

Hydrocarbons are formed on hydrolysis of Grignard compounds by water or hydroxyl-containing substances 438... 

Water, alcohols and hydroxy compounds generally, and also primary and secondary amines, give the hydrocarbon corresponding to the Grignard reagent,... 

Cesium forms simple alkyl and aryl compounds that are similar to those of the other alkah metals (6). They are colorless, sohd, amorphous, nonvolatile, and insoluble, except by decomposition, in most solvents except diethylzinc. As a result of exceptional reactivity, cesium aryls should be effective in alkylations wherever other alkaline alkyls or Grignard reagents have failed (see Grignard reactions). Cesium reacts with hydrocarbons in which the activity of a C—H link is increased by attachment to the carbon atom of doubly linked or aromatic radicals. A brown, sohd addition product is formed when cesium reacts with ethylene, and a very reactive dark red powder, triphenylmethylcesium [76-83-5] (C H )2CCs, is formed by the reaction of cesium amalgam and a solution of triphenylmethyl chloride in anhydrous ether. 

Evidently, the types of compound compatible with this mixture are not many, but it has been used successfully for various 1,3-dioxacycloalkanes and hydrocarbons. It must not be used with halogen compounds although chloro- and bromo-alkanes can be dried safely over sodium films, provided that they are initially at least Grignard dry and free of oxygen. In the author s laboratory specimens of CHjClj and MeBr which had been over sodium films under vacuum for several years were analysed and found to contain only traces of the Wurtz-condensation products. 

Organometallics are generally strong nucleophiles and bases. They react with weak acids, e.g. water, alcohol, carboxylic acid and amine, to become protonated and yield hydrocarbons. Thus, small amounts of water or moisture can destroy organometallic compounds. For example, ethylmag-nesium bromide or ethyllithium reacts with water to form ethane. This is a convenient way to reduce an alkyl halide to an alkane via Grignard and organolithium synthesis. 

Fluorine can be introduced into alkanes indirectly by treating either lithium or Grignard reagents with fluorine (Fig. 70) [165] at -60°C in hydrocarbon ether solvents. The lithium reagents reacted more rapidly than the corresponding Grignard reagents, and primary or secondary alkyl compounds were more reactive than tertiary. 

Optical resolution of some hydrocarbonds and halogeno compounds by inclusion complexation with the chiral host (9a) has been accomplished.11,12 Preparation of optically active hydrocarbons is not easy and only a few example of the preparation of optically active hydrocarbons have been reported. For example, optically active 3-phenylcyclohexene has been derived from tartaric acid through eight synthetic steps.11 Although one-step synthesis of optically active 3-methylcyclohexene from 2-cyclo- hexanol by the Grignard reaction using chiral nickel complex as a catalyst has been reported, the enantiomeric purity of the product is low, 15.9%.11 In this section, much more fruitful results by our inclusion method are shown. 

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