Answer: A biaryl (Ar-Ar).
- A A biaryl (Ar-Ar)
- B A phenol
- C An aryl amine
- D An aryl ketone
Correct answer: A. A biaryl (Ar-Ar)
Explanation: The Ullmann coupling: 2 ArX + Cu → Ar-Ar + CuX₂. This is a classic method for forming biaryl compounds used in pharmaceutical and materials synthesis.
SN2 proceeds in a single step with backside attack and inversion of configuration, while SN1 forms a planar carbocation intermediate first, leading to racemisation.
Concept context
Study carbon-halogen compounds: how they are made, how they react via SN1/SN2 and elimination, their stereochemistry, and their environmental impact.