Of Grignard reagent

Diethyl ether is a mobile, colourless liquid having b.p. 35° and dy 0720. It has a characteristic odour, and a burning taste. It is used chiefly as a solvent, and was formerly widely used as an anaesthetic owing to its chemical non-reactivity, it is very seldom used actually as a reagent, except in the preparation of Grignard reagents (p. 280) where probably its chemical properties reinforce its solvent action. 

Pure Ether. Pure ether (entirely free in particular from water) is frequently required in the laboratory, and especially for the preparation and use of Grignard reagents. It is best prepared in quantity for classes by adding an ample quantity of granular calcium chloride to a Winchester bottle of technical ether, and allowing the mixture to stand for at least 24 hours, preferably with occasional shaking. The greater part of the water and... 

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

These compounds are soluble in ether, are comparatively stable, and exhibit many of the reactions of Grignard reagents but are more reactive. Because of their greater reactivity, organohthium compounds can often be used where Grignard reagents fail thus they add to the azomethine linkage in pyridines or... 

The main use of organocadmium compounds is for the preparation of ketones and keto-esters, and their special merit lies in the fact that they react vigorously with acid chlorides of all types but add sluggishly or not at all to multiple bonds (compare addition of Grignard reagents to carbonyl groups). Some t3rpical syntheses are ... 

The reaction of Grignard reagents with a carbonyl group can be understood as an insertion reaction of an unsaturated C=0 bond of the carbonyl group into... 

Organolithium and -magnesium compounds. Compared with extensive studies carried out on the Ni-catalyzed transmetallation reaction of Grignard reagents[43I,432], few examples of the Pd-catalyzed reactions of Mg are... 

The mam synthetic application of Grignard reagents is their reaction with certain carbonyl containing compounds to produce alcohols Carbon-carbon bond formation is rapid and exothermic when a Grignard reagent reacts with an aldehyde or ketone... 

An ability to form carbon-carbon bonds is fundamental to organic synthesis The addition of Grignard reagents to aldehydes and ketones is one of the most frequently used reactions m synthetic organic chemistry Not only does it permit the extension of carbon chains but because the product is an alcohol a wide variety of subsequent func tional group transformations is possible... 

Secondary alcohols may be prepared by two different combinations of Grignard reagent and aldehyde... 

Three combinations of Grignard reagent and ketone give rise to tertiary alcohols... 

Alcohol synthesis via the reaction of Grignard reagents with carbonyl com pounds (Section 14 6) This is one of the most useful reactions in synthetic organ ic chemistry Grignard reagents react with formaldehyde to yield primary alco hols with aldehydes to give secondary alcohols and with ketones to form terti ary alcohols... 

Reaction of Grignard reagents with es ters (Section 14 10) Tertiary alcohols in which two of the substituents on the hy droxyl carbon are the same may be pre pared by the reaction of an ester with two equivalents of a Grignard reagent... 

Synthesis of alcohols using organolithi um reagents (Section 14 7) Organolithi um reagents react with aldehydes and ketones in a manner similar to that of Grignard reagents to produce alcohols... 

Reaction of Grignard reagents with aldehydes and ketones (Section 14 6)... 

We saw an example of nucleophilic ring opening of epoxides in Section 15 4 where the reaction of Grignard reagents with ethylene oxide was described as a synthetic route to primary alcohols... 

The reaction of Grignard reagents with epoxides is regioselective m the same sense Attack occurs at the less substituted carbon of the ring... 

Addition of Grignard reagents and organolithium compounds (Sections 14 6-14 7) Aldehydes are converted to secondary alcohols and ketones to tertiary alcohols... 

SYNTHESIS OF CARBOXYLIC ACIDS BY THE CARBOXYLATION OF GRIGNARD REAGENTS... 

Synthesis of Carboxylic Acids by the Carboxylation of Grignard Reagents... 

Overall the carboxylation of Grignard reagents transforms an alkyl or aryl halide to a carboxylic acid in which the carbon skeleton has been extended by one carbon atom... 

Organolithium reagents react in the same way and are often used instead of Grignard reagents... 

In fact, the use of dioxane to precipitate MgX2 from solutions of Grignard reagents is a standard method of preparation for solutions of diorganomagnesium compounds. Numerous methods have been used to estabUsh the nature of Grignard reagents in solution and this work has been reviewed (9). 

A number of continuous processes for the manufacture and use of Grignard reagents have been proposed (40), but are of no current commercial significance. 

Crystal stmctures of Grignard reagents do not necessarily correspond to their stmcture in solution. In general, the crystal stmctures (61—64) indicate the reagents are ligated with THF or diethyl ether and are frequentiy observed to be dimers. The Mg atoms in the dimers do not have a Mg—Mg bond instead the dimers are typically held together by a haUde bridge. 

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