Aryl nitrenium ions from N-alkyl-N-arylamino-diazonium precursors: synthesis and reactivityElectronic supplementary information (ESI) available: General procedures, spectral data of previously unknown substrates, reaction optimizations, and crossover experiments. CCDC 923835. See DOI: 10.1039/c3sc52805g

• Main Authors: Huh, Chan Woo, Aubé, Jeffrey
• Format: Journal Article
• Language: English
• Published: 23.12.2013
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c3sc52805g

A means of generating an N -alkyl- N -arylaminodiazonium ion, which then loses nitrogen to form a reactive aryl nitrenium intermediate, is described. In this sequence, a set of triazenyl acetonitriles was synthesized by nucleophilic addition of a nitrile anion to an aryl azide followed by temperature-dependent alkylation at either of two nucleophilic triazenyl nitrogen atoms. An α,α-disubstituted acetonitrile and N -arylaminodiazonium moiety (or aryl nitrenium ion upon loss of N 2 ) are embedded in the resulting 1,3,3-trisubsituted triazene, which undergoes liberation and recombination of these two components under acidic conditions to yield an α-arylated acetonitrile containing an all-carbon-quaternary center. We propose that the N -alkyl- N -arylaminodiazonium ion loses nitrogen to generate an aryl nitrenium species, which then reacts with an α,α-disubstituted acetonitrile either at the para - or meta -position of the aromatic ring to afford p -alkylaminoaryl acetonitrile derivatives or 3,3-substituted 1-methylindolin-2-imines, depending on the substrates and conditions. A new means of generating an N -alkyl- N -arylaminodiazonium ion, which then loses nitrogen to form a reactive aryl nitrenium intermediate, is described.