Conformational stability generally dictates that bulky groups reside as far apart as possible (Anti — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

While the Anti conformer ($180^\circ$) minimizes steric repulsion, 2,3-butanediol possesses two adjacent hydroxyl ($-OH$) groups. In the Gauche conformation ($60^\circ$), these polar $-OH$ groups are positioned perfectly to engage in highly stabilizing intramolecular hydrogen bonding, forming a chelate ring that thermodynamically overrules standard steric repulsion.