Bifunctional amine/squaramide catalyst promoted direct aldol addition of an hydantoin surrogate to pyridine 2-carbaldehyde N-oxides to afford aldol adducts bearing two vicinal tertiary/quaternary carbons in high diastereo- and enantioselectivity (dr up to >20:1; ee up to 98%) is reported. Acid hydrolysis of adducts followed by reduction of the N-oxide group yields enantiopure carbinol-tethered quaternary hydantoin-azaarene conjugates with densely functionalized skeletons. DFT studies of the potential energy surface (B3LYP/6-31+G(d) + CPCM (dichloromethane)) of the reaction correlate the activity of different catalysts and support an intramolecular H-bond-assisted activation of the squaramide moiety in the transition state of the catalytic reaction.