Ketone Oximes as NO2 Radical Precursors for Regioselective Iodo-Nitrosylative Cyclization of Unactivated 1,6-Enynes
Mohana Reddy Mutra1, T L Chandana1, Yu-Syuan Chu1
1Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shiquan first Rd, San-min District, Kaohsiung City 807, Taiwan.
Abstract:
A metal-free three-component radical cascade cyclization of unactivated 1,6-enynes has been developed using 1-phenylethan-1-one oxime as a novel in situ nitrogen dioxide (NO2) radical source under I2/aqueous TBHP conditions. This transformation proceeds through a chemo- and regioselective sequence involving NO2· addition to the terminal alkene, 5-exo-dig cyclization onto the alkyne, and iodine trapping of the resulting carbon-centered radical, yielding 4-(iodo(phenyl)methylene)-3-(nitromethyl)-1-tosylpyrrolidines. This strategy avoids transition metals, photocatalysts, or prefunctionalized nitrogen reagents and highlights the previously unexplored potential of oximes as bench-stable NO2-radical donors for cascade transformations.
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