A Highly Diastereoselective Synthesis of α-Hydroxy-β-amino Acid Derivatives via a Lewis Acid Catalyzed Three-Component Condensation Reaction

A very efficient three-component synthesis of a series of syn alpha-hydroxy-beta-amino esters, obtained in high diastereoselection and yield, was realized starting from an aldehyde, benzylamine, and the ketene silyl acetals derived from Ley's lactones. The synthetic protocol was optimized and the above compounds were obtained without the isolation of intermediates. The origin of the observed diastereoselection was investigated through a computational model of the key reaction step.