Question

Which of the following reactions will not result in the formation of carbon-carbon bonds?
A.Cannizzaro reaction
B.Wurtz reaction
C.Reimer-Tiemann reaction
D.Friedel-craft acylation

Answer 1

Hint: The formation of carbon-carbon bonds occurs in case of acylation. Only one reactant is needed for the reaction with some base.

Complete step by step solution:
Let us look the bond formed in each of the reactions:
Cannizaro reaction:
It is a disproportionation reaction. The self reduction and oxidation occurs in an aldehyde molecule. The reduction of aldehyde will give us alcohol and we know an alcohol molecule contains carbon and oxygen bonds. The oxidation of aldehyde gives us carboxylic acid and here also hydroxide group attaches. So no carbon carbon bond formation occurs instead carbon oxygen bond is formed.
In Wurtz reaction two alkyl halides react with sodium in the presence of dry ether to form higher alkane. We know an alkane has a carbon carbon bond so a carbon carbon bond formation occurs in this reaction.
In the Reimer Tiemann reaction ortho formylation of phenol occurs. In this reaction basically an aldehyde attaches on the phenol group on ortho position. Hence, again a carbon carbon bond formation occurs.
In Friedel-craft acylation the acyl molecule gets attached to the aromatic ring generally toluene. It is a type of substitution reaction. Here also carbon carbon bond forms.
Hence all leads to the formation of carbon carbon bond except Cannizaro reaction.

Thus, the correct option is A.

Note:
In 1853, scientist Stanisloa Cannizzaro made the benzyl alcohol and potassium benzoate from benzaldehyde. The acid exists in the form of its salt because of the presence of base which leads to the dissociation of hydrogen. The aldehyde used does not have alpha hydrogen or we can say it is non enolizable.