Catalytic asymmetric synthesis of (-)-arctigenin using a chiral Ir complex

The catalytic asymmetric synthesis of (-)-arctigenin is reported. The central optically pure lactone in-termediate is obtained either from an Ir-catalyzed asymmetric Tishchenko reaction or an asymmetric oxidative lactonization and subsequently converted to 0-iodomethyl-a-methylene-g-butyrolactone. Several recent Negishi coupling protocols were investigated for the introduction of an aryl unit in the presence of the a-methylene-g-butyrolactone. The introduction of a second aryl unit was achieved using a diastereoselective Rh-catalyzed conjugate addition and protonation under protecting-group-free conditions.(c) 2023 Published by Elsevier Ltd.

Automated summary

The catalytic asymmetric synthesis of (-)-arctigenin was achieved through the transformation of the central optically pure lactone intermediate and the introduction of aryl units. Various coupling protocols were studied for the incorporation of the first aryl unit, while a diastereoselective Rh-catalyzed conjugate addition was utilized for the addition of the second aryl unit.