Asymmetric Dihydroxylation-Based Desymmetrization Enabled by Lone-Pair−π Interaction

Lone-pair−π interactions, which form a stabilizing
association between a lone pair of electrons and a π system,
are widely recognized as supramolecular bonds. However, such noncovalent
interactions rarely serve as a key stereocontrolling element in chemical
reactions. Herein, we report a well-engineered lone-pair−π
interaction-directed catalytic system for asymmetric dihydroxylation
(AD)-based desymmetrization. The lone-pair−π interaction
between the C9 carbonyl in mono-cinchona alkaloids
and the electron-deficient phthalazine in the symmetric alkene substrates
was exploited to realize a highly efficient AD-based desymmetrization,
which was difficult to execute following the traditional Sharpless
asymmetric dihydroxylation method.