Alcohols from Reaction of Carbonyl Compounds with Grignard Reagents

Problem 17.7 What reagent would you use to accomplish each of the following reactions  

Problem 17.8 What carbonyl compounds give- the following alcohols on reduction with LiAlH4 Show all possibilities. 

5 Alcohols from Reaction of Carbonyl Compounds with Grignard Reagents 

Interactive to find supplemental problems and stepwise solutions to the design of Grignard syntheses. 

The reaction of Grignard reagents with carbonyl compounds has no direct biological counterpart, because organomagnesium compounds are too 

As examples of their addition to carbonyl compounds, Grignard reagents react with formaldehyde, H2C=0, to give primary alcohols, with aldehydes to give secondary alcohols, and with ketones to give tertiary alcohols. 

Esters react with Grignard reagents to yield tertiary alcohols in which two of the substituents bonded to lire hydroxyl-bearing carbon have come from the Grignard reagent, just as UAIH4 reduction of an ester adds two Itydrogens. 

Carboxylic acids don t give addition products with Grignard reagents because the acidic carboxyl hydrogen reacts with the basic Grignard reagent to 

As with the reduction of carbon) compounds discussed in the previous section, wc 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 ad as nucleophilic carbon anions, or carlnm ums ( 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 in a second step. 

A great many alcohols can be obtained from Grignard reactions, depending on the reactants. For example, Grignard reagents react with formaldehyde, 

to give primary alcohols, with aldehydes to give secondary alco and with ketones to give tertiary alcohols. 

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Alcohols from Reaction of Carbonyl Compounds with Grignard Reagents 613 Problem 17.7 Whaf reagent would you use to accomplish each of the following reactions ... 

In 1912 Victor Grignard received the Nobel prize in chemistry for his work on the reaction that bears his name, a carbon-carbon bond-forming reaction by which almost any alcohol may be formed from appropriate alkyl halides and carbonyl compounds. The Grignard reagent is easily formed by reaction of an alkyl halide, in particular a bromide, with magnesium metal in anhydrous ether. Although the reaction can be written and thought of as simply... 

Reduction of the carbonyl function in acetophenones using sodium in ethanol also produces an alcohol. More complex aromatic alcohols may be prepared from carbonyl compounds by reaction with Grignard reagents followed by hydrolysis (see Chapter 10). 

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