Zbigniew Rafiński

Enantioselective Synthesis of Chromanones Bearing Quaternary Substituted Stereocenters Catalyzed by (1R)-Camphor-Derived N-Heterocyclic Carbenes

A catalytic asymmetric intramolecular crossed-benzoin reaction for the synthesis of chromanones by novel camphor-derived N-heterocyclic carbenes is described. The corresponding chromanones bearing quaternary stereogenic centers were isolated in high yields with high to excellent enantioselectivity.

Novel (−)‐β‐Pinene‐Derived Triazolium Salts: Synthesis and Application in the Asymmetric Stetter Reaction

A series of novel chiral triazolium salts derived from (−)‐β‐pinene were synthesized and found to be highly efficient precatalysts for the enantioselective intramolecular Stetter reaction. The triazolium salts prepared from a single precursor, (−)‐β‐pinene, react with antipodal enantiofacial selectivity in the Stetter reaction to afford mono‐, di‐, and trisubstituted chromanones in excellent yields with excellent stereoselectivity.