2022

Moorthy, Suresh; Castillo, Bonillo Alvaro; Lambert, Hugues; Kalenius, Elina; Lee, Tung-Chun

Aryl diazonium ions are known to be an important intermediate in the divergent synthesis of azo compounds and substituted aromatics. The presence of more than one electrophilic center in a diazonium ion could lead to undesirable side reactions during a synthesis. Herein, we report that the electrophilic α-carbon on a phenyl diazonium [PhN2]+ ion can be selectively deactivated upon host–guest complexation with cucurbit[7]uril (CB7) in aqueous media, achieving a ∼60-fold increase in the half-life of [PhN2]+. Notably, however, the electrophilic nitrogen of the encapsulated diazonium ion remains active towards diazo coupling with strong nucleophiles, allowing the formation of azo compounds using a two-month-old aqueous solution of [CB7–PhN2]+. Our supramolecular approach can open new possibilities for the reactive chemistry of organic molecules in aqueous media.