Chiral Catalyst Optimization Using Both Solid-Phase and Liquid-Phase Methods in Asymmetric Aza Diels−Alder Reactions
作者:Shū Kobayashi、Ken-ichi Kusakabe、Haruro Ishitani
DOI:10.1021/ol005656b
日期:2000.5.1
In the presence of 1-5 mol % of a chiral zirconium catalyst, aza Diels-Alder reactions of aldimines with Danisheisky's dienes proceeded smoothly to afford the corresponding piperidine derivatives in high yields with high enantioselectivities. For the catalyst optimization, solid-phase and liquid-phase methods were successfully used. In the solid-phase approach, polymer-supported (R)-1,1'-binaphthols (BINOLs) have been synthesized and rapid optimization using the solid-phase reactions has been achieved. On the other hand, novel chiral zirconium cyanides were developed as excellent catalysts using the liquid-phase approach.