A Highly Efficient, Large‐Scale, Asymmetric Direct Aldol Reaction Employing Simple Threonine Derivatives as Recoverable Organocatalysts in the Presence of Water

A one‐step O ‐acylation of threonine resulted in a simple and readily available threonine‐surfactant organocatalyst that could efficiently catalyze the direct asymmetric aldol reactions of cyclic and acyclic ketones with a series of aromatic aldehydes in the presence of water at room temperature with good yields (up to 99 %), diastereoselectivities (up to 99:1), and enantiomeric excesses (>99 %). The catalyst can beeasily recovered and reused with no decrease of enantioselectivity after six cycles. This novel catalyst can be efficiently used in large‐scale reactions, with the enantioselectivity being maintained at the same level, which offers great possibilities for application in industry.