Synthesis of Alcohols Using Organolithium Reagents

Reactions of Grignard Reagents with Aldehydes and Ketones 

Grignard reagents react with formaldehyde (CH2=0) to give primary alcohols having one more carbon than the Grignard reagent. 

Reaction with aldehydes Grignard reagents react with aldehydes 

In this particular example, the product can be variously described as a secondary alcohol, a henzy//c alcohol, and an a//y//c alcohol. Can you identify the structural reason for each classification  

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Synthesis of alcohols using organolithium reagents (Section 14.7) Organolithium reagents react with aldehydes and ketones in a manner similar to that of Grignard reagents to produce alcohols. 

Synthesis of Alcohols Using Grignard and Organolithium Reagents... 

All that has been said in this section applies with equal force to the use of organo-lithium reagents in the synthesis of alcohols. Grignard reagents are one source of nucleophilic carbon organolithium reagents are another. Both have substantial carbanionic char acter in their- car bon-metal bonds and undergo the same kind of reaction with aldehydes and ketones. 

An ability to form carbon-carbon bonds is fundamental to organic synthesis. The addition of Grignard and organolithium reagents to aldehydes and ketones is one of the most frequently used reactions in 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 functional group transformations is possible. 

Although the majority of sulfides used as precursors to organolithiums have been thioacetals or sulfides bearing other a-substituents, the usefulness even of simple phenylsulfides related to 56 was demonstrated in the synthesis of dihydroerythronolide A by Stork,74 which used a sulfide intermediate 59 in the conversion of an alcohol to a Grignard reagent. 

Use Grignard and organolithium reagents for the synthesis of primary, secondary, and tertiary alcohols with the needed carbon skeletons. 

Organolithium reagents (sec. 8.5) are also useful precursors. Vinylcerium reagent 180 was prepared from vinyl bromide 179 in Ovaska s synthesis of fused polycyclic ring systems.When this reacted with 181, alcohol 182 was isolated in 61% yield after hydrolysis. 

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