Enantioselective Synthesis of Densely Functionalized Pyranochromenes via an Unpredictable Cascade Michael–Oxa‐Michael–Tautomerization Sequence

A surprising example of enantioselective cascade Michael–oxa-Michael–tautomerization reactions of malononitrile and benzylidenechromanones has been developed. In this case, malononitrile functions as both nucleophile and electrophile. Meanwhile, a simple bifunctional indane amine–thiourea catalyst has been discovered to promote this process to afford high yields (up to 99%) and high to excellent enantiomeric excesses (81–99% ee).