Stereoselective Diazenylation of β,β-Disubstituted Enesulfinamides with Aryldiazonium Cations

The direct nucleophilic reaction of β,β-disubstituted enesulfinamides with aryldiazonium tetrafluoroborates enables the stereoselective synthesis of α-diazenylated ketimines. In this process, the defined geometry of the C═C bond and the absolute configuration of the sulfinyl group within the enesulfinamides jointly govern the stereochemical outcome during C-N bond formation. The resulting enantioenriched acyclic α-diazenylated carbonyl derivatives feature two α-substituents with comparable steric and electronic properties (e.g., methyl and ethyl groups), representing products that cannot be accessed through existing direct asymmetric diazenylation approaches. Owing to the pronounced electrophilicity of the diazonium salts, this transformation proceeds without the necessity for prior deprotonation of the NH group in the enesulfinamides to generate more nucleophilic metalloenamine intermediates.