Question

Which of the following reactions involves copper metal?
A. Wurtz reaction
B. Wurtz-fittig reaction
C. Ullmann reaction
D. Frankland reaction

Answer 1

Hint: Metals are usually used in the reaction to provide the reaction medium with electrons. Metals easily give away electrons and get oxidized. This causes the halides to accept electrons and combine with cation of metal, and the remaining alkyls or aryls get coupled.

Complete answer:
The Wurtz reaction is a coupling reaction in organic chemistry, organometallic chemistry and recently inorganic main group polymers, in this reaction two alkyl halides are reacted with sodium metal in dry ether solution to form a higher alkane.
The Wurtz–Fittig reaction is the chemical reaction of aryl halides with alkyl halides and sodium metal in the presence of dry ether to give substituted aromatic compounds as their products.
The Ullmann reaction or Ullmann coupling is a coupling reaction between aryl halides and copper. It gives two aryl compounds coupled together.
The preparation of dialkyl zinc from zinc and alkyl iodide is called the Frankland reaction. Alkyl zinc has found many applications in organic synthesis because its addition to aldehydes in the presence of a chiral catalyst affords secondary alcohols with a high level of enantio-selectivity.
So, the correct answer is Option C, Ullmann reaction.

Note: The Ullmann reaction is an organic reaction which is used to couple two molecules of aryl halide to form a biaryl using copper metal and optimum thermal conditions. There is a radical mechanism proposed which begins with a single electron transfer (SET) from the copper metal to the alkyl halide to form an aryl radical. Two aryl radicals then react to form the final biaryl product.