Asymmetric hydrogenation of (6-methoxyl-2-naphthyl)-2-acrylic acid catalyzed by cinchona modified Pd(0)-a-FeOOH was reported and ee抯 of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic acid ((S)-(+)-naproxen) up to 98% ...Asymmetric hydrogenation of (6-methoxyl-2-naphthyl)-2-acrylic acid catalyzed by cinchona modified Pd(0)-a-FeOOH was reported and ee抯 of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic acid ((S)-(+)-naproxen) up to 98% was achieved firstly.展开更多
Tetracyclic coumarins are a class of important compounds with diverse and superior pharmacolog‐ical activities.However,a direct stereoselective method from simple and readily‐made coumarins derivatives remains chall...Tetracyclic coumarins are a class of important compounds with diverse and superior pharmacolog‐ical activities.However,a direct stereoselective method from simple and readily‐made coumarins derivatives remains challenging due to the inertness of coumarins as dienophiles.Herein,we de‐velop a decarboxylative asymmetric[4+2]cycloaddition of 3‐cyanocoumarins with vinyl benzoxa‐zinones,affording the coumarin‐derived condensed rings bearing three continuous stereocenters in high yields with excellent diastereoselectivities(>20/1 d.r.)and enantioselectivities(up to 99%ee).This direct enantioselective reaction was achieved by a Pd(0)/Cu(I)bimetallic catalytic system.The mechanism studies indicated that the synergistic activation effect,in which chiral Cu(I)as an availa‐ble Lewis acid catalyst activates 3‐cyanocoumarin and chiral Pd(0)complex activates benzoxazi‐none by the formation ofπ‐allyl‐palladium intermediate,plays an important role on the stereoselec‐tive control.The current work provides a new activation modes of Cu catalyst in the Pd/Cu bimetal‐lic catalytic system.展开更多
文摘Asymmetric hydrogenation of (6-methoxyl-2-naphthyl)-2-acrylic acid catalyzed by cinchona modified Pd(0)-a-FeOOH was reported and ee抯 of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic acid ((S)-(+)-naproxen) up to 98% was achieved firstly.
文摘Tetracyclic coumarins are a class of important compounds with diverse and superior pharmacolog‐ical activities.However,a direct stereoselective method from simple and readily‐made coumarins derivatives remains challenging due to the inertness of coumarins as dienophiles.Herein,we de‐velop a decarboxylative asymmetric[4+2]cycloaddition of 3‐cyanocoumarins with vinyl benzoxa‐zinones,affording the coumarin‐derived condensed rings bearing three continuous stereocenters in high yields with excellent diastereoselectivities(>20/1 d.r.)and enantioselectivities(up to 99%ee).This direct enantioselective reaction was achieved by a Pd(0)/Cu(I)bimetallic catalytic system.The mechanism studies indicated that the synergistic activation effect,in which chiral Cu(I)as an availa‐ble Lewis acid catalyst activates 3‐cyanocoumarin and chiral Pd(0)complex activates benzoxazi‐none by the formation ofπ‐allyl‐palladium intermediate,plays an important role on the stereoselec‐tive control.The current work provides a new activation modes of Cu catalyst in the Pd/Cu bimetal‐lic catalytic system.
