Neighboring ortho‐Hydroxy Group Directed Catalytic Asymmetric Triple Domino Reactions of Acetaldehyde with (E)‐2‐(2‐Nitrovinyl)phenols
Herein we demonstrate the utilization of neighboring ortho-hydroxy group participation in the pretransition state of enamine- and iminium-based triple domino reactions for high reactions rates and asymmetric induction. Enantiomerically pure, drug-like chromanes and tetrahydro-6H-benzo[c]chromenes having three to four contiguous stereocenters are synthesized through triple domino Michael/aldol/oxa-Michael reactions catalyzed by (R)-2-{diphenyl[(trimethylsilyl)oxy]methyl}pyrrolidine followed by Wittig and Michael/Wittig–Horner reactions from simple precursors under mild conditions.