The first palladium-catalyzed asymmetric addition of arylboronic acids to coumarins was successfully established, providing a straightforward asymmetric approach to achieving pharmaceutically important 4-aryl-3,4-dihydrocoumarins. This methodolo-gy features easily accessible and bench-stable ligands, a wide substrate scope, mild conditions and good accommodation of challenging, electron-withdrawing arylboronic acids.
Disclosed in this communication is a novel asymmetric addition of alkynyl nucleophiles to <i>N</i>-alkyl pyridinium electrophiles. The coupling is effected under mild and simple reaction conditions, affording dihydropyridine products with complete regiochemical and stereochemical control. In addition to several manipulations of the dihyropyridine products, the utility of this transformation is demonstrated through a concise, dearomative, and asymmetric synthesis of (+)-lupinine, a natural acetylcholine esterase inhibitor.
Disclosed in this communication is a novel asymmetric addition of alkynyl nucleophiles to <i>N</i>-alkyl pyridinium electrophiles. The coupling is effected under mild and simple reaction conditions, affording dihydropyridine products with complete regiochemical and stereochemical control. In addition to several manipulations of the dihyropyridine products, the utility of this transformation is demonstrated through a concise, dearomative, and asymmetric synthesis of (+)-lupinine, a natural acetylcholine esterase inhibitor.
Palladium Catalyzed Enantioselective Hayashi-Miyaura Reaction for Pharmaceutically Important 4-Aryl-3,4-Dihydrocoumarins
