Recyclable chiral diamine–polyoxometalate (POM) acids catalyzed asymmetric direct aldol reaction of aromatic aldehydes with long-chain aliphatic ketones

In this Letter, we studied the asymmetric direct aldol reaction of long-chain aliphatic ketones with aromatic aldehydes, using chiral diamine–polyoxometalate acid combined organocatalysts. High yields (up to 90%) and enantioselectivities (up to 90% ee) were obtained under solvent-free conditions with the optimized catalyst. Furthermore, such organocatalysts could be easily recycled and reused for four times without significant loss of reactivity and enantioselectivity.