Chiral catalyst optimization using both solid-phase and liquid-phase methods in asymmetric aza Diels-Alder reactions

In the presence of 1-5 mol % of a chiral zirconium catalyst, aza Diels-Alde r reactions of aldimines with Danisheisky's dienes proceeded smoothly to af ford the corresponding piperidine derivatives in high yields with high enan tioselectivities. For the catalyst optimization, solid-phase and liquid-pha se methods were successfully used. In the solid-phase approach, polymer-sup ported (R)-1,1'-binaphthols (BINOLs) have been synthesized and rapid optimi zation using the solid-phase reactions has been achieved. On the other hand , novel chiral zirconium cyanides were developed as excellent catalysts usi ng the liquid-phase approach.