Organocatalytic asymmetric synthesis of oxazolines from N-acylimines

A novel organocatalytic asymmetric approach to oxazoline derivatives that proceeds through Mannich/annulation reaction of N-acylimines with 3-chlorooxindoles is presented. This strategy provides an efficient and convenient method to access enantioenriched oxazolines such as valuable chiral S,N-oxazoline ligand as well as Ferrox ligand in high yields with excellent enantio- and diastereroselectivity. Furthermore, the optically active oxazoline products can be converted to valuable 1,2-amino alcohols. More importantly, the synthetic utility of this transformation is demonstrated in the expeditious assembly of chiral Phox-type ligand, which shows excellent catalytic activities.