Grignard reagent ketone

Nakamura E, Kubota K, Sakata G, Addition of zincated hydrazone to vinyl grignard reagent, Ketone synthesis by one-pot assembly of four components, J. Am. Chem. Soc., 119 5457-5458, 1997. 

Also, experimental problems not considered by the adherents of the complex theory were observed (76). For example, it was found that the precipitate formed from fenchone and CgHjMgBr in ether and earlier claimed to be the Grignard reagent/ketone complex (the ketone indeed could be regenerated from the complex) contained MgBr2 rather than C.HjMgBr. 

Earlier work [151] showed that at high temperature, isonitriles isomerize into nitriles. Isonitriles have recently [152] been isomerized at much lower temperatures by reacting them with alkyl lithium or Grignard reagents. Ketones are simultaneously formed in amounts which vary with the structure of the alkyl—... 

A review article by Ashby (based on a plenary lecture) on the Grignard reagent-ketone reaction has appeared. The first example of electron transfer in reactions of primary Grignard reagents with ArgCO has been reported. The cyclized product (8), in Scheme 3, from the specifically designed Grignard (9),... 

Esters (a) and acid chlorides (6) readily react with Grignard reagents to give ketones, which immediately react with a second equivalent of the reagent as in (5) to give tertiary alcohols as before. 

Nitriles also react w ith Grignard reagents to give ketones, which arise from the hydrolysing action of the dilute sulphuric acid on the intermediate addition product. Acid amides beha e similarly. 

The Reformatsky Reaction consists of the interaction of an ester of an a-halogeno-acid with an aldehyde, a ketone or another ester in the presence of zinc. For example, if a mixture of ethyl bromoacetate and benzaldehyde is heated with zinc, the latter undoubtedly first combines with the ethyl bromoacetate to form a Grignard-like reagent (reaction A), which then adds on to the benzaldehyde Just as a Grignard reagent would do (reaction B). The complex so formed, on acidification gives ethyl p-phenyl-p-hydroxy-propionate (reaction C). Note that reaction A could not satisfactorily be carried out using... 

Action of the Grignard reagent upon a ketone, for example ... 

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 Grignard reagent might first attack the ketone gifting the wrong produet. 

It should be noted that Grignard reagents obtained from 2-methylthiazole do not yield acetyl derivatives (31). Ketones can also be obtained from cyanothiazoles and Grignard reagents (87). Thus phenyl magnesium bromide and 5-cyanothiazole give phenyl 5-thiazolyl ketone (Scheme 35). 

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... 

The type of alcohol produced depends on the carbonyl compound Substituents present on the carbonyl group of an aldehyde or ketone stay there—they become sub stituents on the carbon that bears the hydroxyl group m the product Thus as shown m Table 14 3 (following page) formaldehyde reacts with Grignard reagents to yield pri mary alcohols aldehydes yield secondary alcohols and ketones yield tertiary alcohols... 

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... 

FIGURE 14 2 Aretrosyn thetic analysis of alcohol preparation by way of the addition of a Grignard reagent to an aldehyde or ketone... 

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

Tertiary alcohols can be prepared by a variation of the Grignard synthesis that uses esters as the source of the carbonyl group Methyl and ethyl esters are readily available and are the types most often used Two moles of a Grignard reagent are required per mole of ester the first mole reacts with the ester converting it to a ketone... 

The ketone is not isolated but reacts rapidly with the Grignard reagent to give after adding aqueous acid a tertiary alcohol Ketones are more reactive than esters toward... 

Grignard reagents and so it is not normally possible to interrupt the reaction at the ketone stage even if only one equivalent of the Grignard reagent is used... 

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... 

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... 

Sodium acetylide and acetylenic Grignard reagents react with aldehydes and ketones to give alcohols of the type... 

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

Sodium borohydride and lithium aluminum hydride react with carbonyl compounds in much the same way that Grignard reagents do except that they function as hydride donors rather than as carbanion sources Figure 15 2 outlines the general mechanism for the sodium borohydride reduction of an aldehyde or ketone (R2C=0) Two points are especially important about this process... 

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

We ve seen how Grignard reagents add to the carbonyl group of aldehydes ketones and esters Grignard reagents react m much the same way with carbon dioxide to yield mag nesium salts of carboxylic acids Acidification converts these magnesium salts to the desired carboxylic acids... 

Write an equation showing how you could prepare ethyl phenyl ketone from propanenitrile and a Grignard reagent What is the structure of the imine intermediate ... 

Section 20 20 Nitriles are useful starting materials for the preparation of ketones by reaction with Grignard reagents... 

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