Grignard reagents, reactions with carbonyl compounds

Products from the Reaction of Grignard Reagents (RMgX) with Carbonyl Compounds... 

As with the reduction of carbonyl compounds discussed in the previous section, we ll defer a detailed treatment of the mechanism of Grignard reactions until Chapter 19. For the moment, it s sufficient to note that Grignard reagents act as nucleophilic carbon anions, or carbanions ( R ), and that the addition of a Grignard reagent to a carbonyl compound is analogous to the addition of hydride ion. The intermediate is an alkoxide ion, which is protonated by addition of F O"1 in a second step. 

Reaction of a-phenylsulfinyl acetate or ethyl a-(t-butylsulfmyl)acetate with one equivalent of ethylmagnesium bromide or iodide was shown to give the corresponding Grignard reagent 129 or 132, which upon reaction with carbonyl compounds afforded the corresponding adducts. Thus Nokami and coworkers prepared ethyl / -hydroxycarboxylates 130167, jS-keto esters 131168, a,/J-unsaturated esters 133169 and other derivatives by this method. 

Bis(dialkylamino)cyclopropenylium magnesium halides, like their lithium counterparts, react as nucleophiles in various reactions, but their use is much less extensive. Like typical Grignard reagents they undergo hydrolysis, alkylation and reactions with carbonyl compounds at the carbenoid carbon (equation 292)357. 

Phenylytterbium iodide, C6H5YbI. This reagent can be prepared by reaction of C6H5I with Yb powder in THF. In reactions with carbonyl compounds, it behaves in the same way as Grignard reagents, except that it reacts more readily with esters than with ketones.12... 

QUESTION What would be the result if water were accidentally added in the first reaction with the Grignard reagent and the carbonyl compound ... 

The majority of main group organometallic compounds for which SET mechanisms were postulated involves Grignard reagents [13,69-75] in their reactions with carbonyl compounds. Even the formation of these important laboratory reagents RMgHal (which does not fall within the scope of this article) is now believed to involve electron transfer mechanisms and radical formation at the surface of metallic Mg [76,77]. In contrast to Grignard compounds with their... 

Although this type of reduction is most frequently observed in reactions with carbonyl compounds, several different types of organic substrates have been reported to undergo reduction by a Grignard reagent. 

Addition of a Grignard reagent to a carbonyl compound is a versatile reaction that forms a new C—C bond. This reaction can produce compounds with a variety of structures because both the structure of the carbonyl compound and the structure of the Grignard reagent can be varied. 

For the same reason, we must consider the structure of the carbonyl compound selected for reaction with a Grignard reagent. If the carbonyl compound also contains a hydroxyl group, the fastest reaction will be the destruction of the added Grignard reagent by protonation. 

Field L, Boyd ET. Grignard reagents of sulfones. 7. Additional reactions with carbonyl compounds. 7. Org. Chem. 1961 26(6) 1787-1790. 

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... 

Alcohol synthesis via the reaction of Grignard reagents with carbonyl compounds (Section 14.6) This is one of the... 

Alcohols from Reaction of Carbonyl Compounds with Grignard Reagents 613... 

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