Ascorbic Acid, Vitamin C
Aryl radicals generated in situ from arene diazonium fluoroborates promoted by ascorbic acid enable a convenient and general oxidative arylation of vinyl arenes in air at room temperature in the absence of any additive and visible light irradiation. Various 2-aryl acetophenones have been obtained in good yields.
B. Majhi, D. Kundu, B. C. Ranu, J. Org. Chem., 2015, 80, 7739-7745.
In situ nitrosation of anilines followed by reduction with ascorbic acid to form aryl radicals and thiolation with disulfides provided aryl sulfides. This mild, metal-free synthesis of aryl sulfides proceeded smoothly without heating or irradiation. This strategy can be expanded to the synthesis of aryl selenides.
M.-j. Bu, G.-p. Lu, C. Cai, Synlett, 2015, 26, 1841-1846.
An iridium photocatalyst enables the addition of fluorinated groups to nitrones using ascorbic acid as a stoichiometric reducing agent. Partially fluorinated alkyl iodides can also be effectively used. The resulting hydroxylamines can be readily converted to valuable fluorinated amines by reduction with zinc.
V. I. Supranovich, V. V. Levin, M. I. Struchkova, A. D. Dilman, Org. Lett., 2018, 20, 840-843.