Highly Enantioselective Dihydroxylation of 1,1-Disubstituted Aliphatic Alkenes Enabled by Orchestrated Noncovalent π-Interactions

The elusive nature of noncovalent pi-interactions leads to their infrequent use as a design element in challenging chemical reactions. Stereocontrolling models based on coordinated noncovalent pi-interactions were used for the asymmetric dihydroxylation of 1,1-disubstituted aliphatic alkenes. By introduction of a substituted phthalazine ring into the alkene substrates, the enantioselectivity reached 99% under the catalysis of bis-cinchona alkaloid ligands. Density functional theory calculations indicated a well-orchestrated, pi-pi interaction-directed "sandwich-like" transition state.