Evans oxazolidinone-based alkylations and Sharpless ligand-based dihydroxylations are two powerful methodologies for incorporating new stereogenic centers. Interestingly, prior to our efforts in this area, little attention had been paid to the combination of these two technologies. Matched/mismatched relationships between Evans' oxazolidinones and Sharpless' ligands based on pi-stacking of the auxiliary will be discussed. Cleavage of Evans' oxazolidinone 3 to benzyl ester 4 led to improved yields and increased diastereoselectivity. Application of this protocol to an improved synthesis of the C₁₃-C₁₉ fragment of azaspiracid-1 will be disclosed.