Formation of Highly Stable 1,2-Dicarbonyl Organic Radicals from Cyclic (Alkyl)(amino)carbenes.

Two air-stable organic radicals derived from oxalyl chloride and cAAC were synthesized, resulting in the unexpected formation of a known (amino)(carboxy) radical cation ([ 2 ]BF 4 ) and the oxidative formation of a 1,2-dicarbonyl radical cation ([ 3 ]BF 4 ) from a neutral 3-oxetanone compound ( 4 ). The highly strained and newly discovered 4 was obtained by a single-electron reduction of [ 3 ]BF 4 with a mild reducing agent. This result differs from the generation of NHC-based 1,2-dicarbonyl radicals, indicating the uniqueness of cAAC.