Chiral Phosphoric Acid Scaffolds. Chiral phosphoric acid (CPA) catalysts mediate a vast array of enantioselective transformations. The axially chiral scaffold asymmetrically hinders the binding site around the phosphoric acid moiety, encouraging selectivity. Diverse CPA backbones and scaffolds have been designed to sterically modulate the phosphoric acid site. Some of the most employed scaffolds include BINOL and SPINOL backbones (Figure ). Variants of these scaffolds were considered to assess the ability of SMART to parametrize the steric hindrance of the reactive sites of CPAs (Figure ).