Crystallization-Enabled Stereoconvergent Michael Additions of β-Keto Esters to Nitroolefins.

Asymmetric Michael additions are powerful tools to meet the growing need for stereochemically complex products. While 1,3-dicarbonyls are common nucleophiles, the successful use of configurationally unstable β-keto esters in diastereoselective variants remains understudied. In this Letter, crystalline β-keto esters were leveraged in a two-phase, one-pot merger of an asymmetric Michael addition with a crystallization-induced diastereomer transformation. Tuning the crystallinity of β-keto ester adducts enabled stereoconvergence of the products, which were isolated by filtration.