2-Azaadamantane N-Oxyl, AZADO
2-Azaadamantane N-Oxyl (AZADO) is a less hindered nitroxyl radical, that exhibits an enhanced reactivity compared with TEMPO.
Recent Literature
The use of tert-butyl nitrite as the co-catalyst in a 2-azaadamantane-N-oxyl
(AZADO)- and 9-azanoradamantane-N-oxyl (nor-AZADO)-catalyzed efficient
aerobic oxidation of primary alcohols in MeCN instead of the previously reported
AcOH provides the corresponding aldehydes selectively. The addition of saturated
aqueous NaHCO3 after the completion of the reaction suppresses the
overoxidation of the product during the workup.
M. Shibuya, K. Furukawa, Y. Yamamoto,
Synlett, 2017, 28, 1554-1557.
A stable nitroxyl radical class of catalysts, 2-azaadamantane N-oxyl (AZADO) and
1-Me-AZADO, exhibit superior catalytic proficiency to TEMPO, converting various
sterically hindered alcohols to the corresponding carbonyl compounds in
excellent yields.
M. Shibuya, M. Tomizawa, I. Suzuki, Y. Iwabuchi, J. Am. Chem. Soc., 2006,
128, 8412-8413.
A smooth, organocatalytic one-pot oxidative cleavage of terminal 1,2-diols to
one-carbon-unit-shorter carboxylic acids is catalyzed by 1-Me-AZADO in the
presence of a catalytica amount of NaOCl and NaClO2 under mild
conditions. A broad range of substrates including carbohydrates and N-protected
amino diols were converted without epimerization.
M. Shibuya, R. Doi, T. Shibuta, S.-i. Uesugi, Y. Iwabuchi, Org. Lett., 2012,
14, 5006-5009.
A chemoselective oxidation of α-hydroxy acids to α-keto acids is catalyzed by
2-azaadamantane N-oxyl (AZADO), a nitroxyl radical catalyst. The use of
molecular oxygen as a cooxidant enables the desired chemoselective oxidation to
α-keto acids, that are labile and can easily release CO2 under
oxidation conditions.
K. Furukawa, H. Inada, M. Shibuya, Y. Yamamoto, Org. Lett.,
2016, 18, 4230-4233.
