An umpolung of Lewis acidity/basicity at nitrogen by deprotonation of a cyclic (amino)(aryl)nitrenium cation

• DOI: 10.1039/c8cc01331d
• Publication Date: 2018-03-05T15:33:58Z
• Authors: Jiliang Zhou; Liu Leo Liu; Levy L. Cao; Douglas W. Stephan
• Keywords: Umpolung

A cyclic (amino)(aryl)nitrenium cation 2 has been achieved by treatment of spiro[fluorene-9,3'-indazole] (1) with Ph2CHCl and AgBF4. This is Lewis acidic at nitrenium N1, reacting PMe3 affording a acid/base adduct 3. In contrast, deprotonation other bases provides neutral compound 4 which basic electrophiles including GaCl3, MeOTf PhNCO.