The synthesis of piperidines and piperidines derivatives in enantiopure fashion have been a challenging goal for organic chemists. In this report we developed a nice cascade reaction for piperidine derivatives based in an amidomalonate Michael addition to enals followed by an intramolecular hemiaminal formation with good yields and enantioselectivities.
Moreover we studied the "in situ" intramolecular cyclization of this hemiaminals with alcohols forming fused piperidine-oxazolidines.