Asymmetric Ring Opening of meso-Epoxides with Aromatic Amines Using (R)-(+)-BINOL-Sc(OTf)3-NMM Complex as an Efficient Catalyst

This work reports the asymmetric ring‐opening reaction of meso‐epoxides with aromatic amines by using the highly efficient in situ generated (R)‐(+)‐BINOL‐Sc(OTf)3‐N‐methylmorpholine complex. The asymmetric ring opening of cis‐stilbene oxide with various substituted aromatic amines gave enantioenriched β‐amino alcohols in good yields and with excellent enantioselectivities when the reaction was conducted at 0 °C for 12 h. The reaction proceeded under mild conditions using simple and inexpensive starting materials such as (R)‐(+)‐1,1′‐bi‐2‐naphthol [(R)‐(+)‐BINOL], meso‐stilbene oxide, aniline derivatives, and 4 Å molecular sieves. This new and versatile catalytic system has competitive advantages such as short reaction times, no additives, and no expensive chiral ligands that require a multistep synthesis under harsh reaction conditions. A simple and efficient protocol was developed for the asymmetric ring opening of a meso‐epoxide with various amines using a chiral scandium complex. The system was optimized with respect to various reaction parameters. Under mild conditions, the reaction afforded a wide variety of enantiomerically pure β‐amino alcohols in high yields and with excellent enantioselectivities.