A recyclable non-immobilized siloxy serine organocatalyst for the asymmetric direct aldol reaction

A recyclable siloxy-l-serine organocatalyst has been developed to catalyze asymmetric direct aldol reactions in [bmim][BF4], furnishing the β-hydroxy carbonyl scaffold in high enantio- and diastereoselectivities using a selection of aromatic aldehydes and cycloalkanes. The siloxy serine organocatalyst in the ionic liquid can be reused for up to four successive cycles with comparable enantioselectivities.