anti-Selective asymmetric synthesis of β-hydroxy-α-amino acid esters by the in situ generated chiral quaternary ammonium fluoride-catalyzed Mukaiyama-type aldol reaction

The aldol coupling of ketene silyl acetal 2 derived from the glycinate Schiff base with aldehydes can be efficiently catalyzed by an in situ generated, chiral quaternary ammonium fluoride of type I under mild, neutral conditions, affording the corresponding anti-beta-hydroxy-alpha-amino esters predominantly with excellent enantioselectivities.