Asymmetric Synthesis of Dihydrocoumarins Containing Contiguous Quaternary and Tertiary Stereogenic Centers Catalyzed by a Cinchona ‐Alkaloid‐Based Bifunctional Thiourea Derivative

A series of enantiomerically enriched 3,4‐dihydrocoumarins containing contiguous quaternary and tertiary stereogenic centers has been efficiently constructed via domino asymmetric Michael addition/transesterification reactions of azlactones with o ‐hydroxychalcones using a quinine‐derived thiourea as bifunctional organocatalyst. Under mild reaction conditions, the optically active 3,4‐dihydrocoumarins were generally obtained in 63–96% yields with >20:1 dr and 81–96% ee .