Utilization of Donor-Acceptor Interactions for the Catalytic Acceleration of Nucleophilic Additions to Aromatic Carbonyl Compounds.

A conceptually new method for the catalytic electrophilic activation of aromatic carbonyl substrates, by utilizing donor-acceptor interactions between an electron-deficient macrocyclic boronic ester host ([2+2] ) and an aromatic carbonyl guest substrate, was realized. In the presence of a catalytic amount of [2+2] , dramatic acceleration of the nucleophilic addition of a ketene silyl acetal towards either electron-rich aromatic aldehydes or ketones was achieved. Several control experiments confirmed that inclusion of the aromatic substrates within [2+2] , through efficient donor-acceptor interactions, is essential for the acceleration of the reaction.