Asymmetric Dearomatic Diels–Alder Reactions of Diverse Heteroarenes via π‑System Activation

An asymmetric dearomatic
Diels–Alder protocol for various
heteroarenes, such as benzofuran, benzothiophene, or even furan, has
been developed via π-system activation. This method involves in situ generation of formal trienamine species embedding
a heteroaromatic moiety, and an array of chiral fused frameworks with
high molecular complexity and skeletal diversity were efficiently
constructed in good to excellent stereoselectivity by the catalysis
of a cinchona-based primary amine.