Nickel-Catalyzed Asymmetric Ring Opening of Oxa­benzo­norborna­dienes with Arylboronic Acids

A new, versatile,
and highly efficient nickel-catalyzed asymmetric
ring-opening (ARO) reaction of oxabenzo­norborna­dienes
with a wide variety of arylboronic acids has been developed, yielding cis-2-aryl-1,2-dihydro­naph­thalen-1-ols in high
yields (up to 99%) with good to excellent enantioselectivities (up
to 99% ee) under very mild conditions. The effects of various nickel
precursors, chiral bidentate ligands, catalyst loadings, bases, solvents,
and temperatures on the yield and enantioselectivity of the reaction
were also investigated. A plausible mechanism was proposed to account
for the formation of the corresponding cis-ring-opened
products based on the X-ray structure of product 4b.