Identify the major product formed in the following reaction sequence:

Step-by-step solution

The given reactant is biphenyl-2,2',6,6'-tetracarbaldehyde, which contains four aldehyde ( -CHO ) groups and lacks any -hydrogens. Treatment with concentrated NaOH initiates a Cannizzaro reaction. Due to the close spatial proximity of the aldehyde groups across the biphenyl bond, the molecule undergoes an intramolecular double Cannizzaro reaction. During this disproportionation process, within each proximate pair of formyl groups, one is oxidized to a carboxylate ion ( -COO^- ) while the other is reduced to a prima