Concise Enantioselective Total Synthesis of Isopavine Alkaloids

Herein, we report a concise asymmetric total synthesis of isopavine alkaloids, which feature a special azabicyclo[3.2.2]nonane tetracyclic skeleton. The key steps include iridium-catalyzed asymmetric hydrogenation of unsaturated carboxylic acids, Curtius rearrangement, and Eschweiler-Clarke methylation, which enable an enantioselective approach to isopavine alkaloids in 6-7 linear steps. Furthermore, for the first time, isopavine alkaloids, especially (-)-reframidine (3), are found to display effective antiproliferative effects on various cancer cell lines.

Automated summary

In this study, we describe a concise and enantioselective total synthesis of isopavine alkaloids with a unique azabicyclo[3.2.2]nonane tetracyclic skeleton. Key steps include iridium-catalyzed asymmetric hydrogenation, Curtius rearrangement, and Eschweiler-Clarke methylation, enabling the synthesis of isopavine alkaloids in 6-7 linear steps. Additionally, we discovered that isopavine alkaloids, particularly (-)-reframidine (3), exhibit significant antiproliferative effects on various cancer cell lines for the first time.