Alcohol Oxidation Catalysts with Higher Activity than TEMPO——AZADOL®
Alcohol Oxidation Catalysts with Higher Activity than TEMPO——AZADOL®
Recently, environmentally friendly oxidation reactions catalyzed by a nitrogen-oxygen radical, TEMPO, have attracted attention. Iwabuchi et al. reported that a nitrogen-oxygen radical, 2-azadamantane-N-oxygen (AZADO), efficiently catalyzed oxidation reaction of alcohols.1-3 Compared with TEMPO, AZADO presents higher oxidizability, which makes it possible to oxidize even sec-alcohols with large site resistance in high yields. In contrast, 2-hydroxy-2-azaadamantane (AZADOL®), developed by Iwabuchi et al. has better storage stability than AZADO. In the presence of an oxidizing agent, this catalytic reaction undergoes the mechanism of AZADO, so that AZADOL® presents the same properties as AZADOL. In addition, the oxidation reaction of nitrogen carbonyl salts derived from AZADOL® has been investigated.
Advantage of AZADOL®
• High catalytic activity (better than TEMPO)
• Prone to oxidize secondary alcohols with high site resistance
• Depending on the co-oxidant, a wide range of oxidation reactions can be applied (Co-oxidant: NaOCl, NaClO2, PhI(OAc)2, O2, DIAD）4
Oxidation of Alcohols under Anelli’s Condition 1-2
Aerobic Oxidation of Alcohols 5
Oxidation of Alcohols to Carbonyl Compounds with Mitsunobu Reagent 6
Functional-group-selective oxidation proceeds by use of Mitsunobu reagent DIAD as a co-oxidant.
One-Pot Oxidative Cleavage of 1,2-Diols to (Di) Carboxylic Acids 7
Oxidative cleavage of 1,2-diols to carboxylic acids proceeds by use of hypervalent iodine compound PhI(OAc)2 as a co-oxidant.
References
1. M. Shibuya, Y. Sasano, M. Tomizawa, T. Hamada, M. Kozawa, N. Nagahama, Y. Iwabuchi, Synthesis 2011, 21, 3418. https://doi.org/10.1055/s-0030-1260257
2. Y. Iwabuchi, M. Shibuya, M. Tomizawa, Y. Osada, PCT Int. Appl. WO 2009145323, 2009.
3. M. Hayashi, M. Shibuya, Y. Iwabuchi, Org. Lett. 2012, 14, 154. https://doi.org/10.1021/ol2029417
4. Y. Iwabuchi, Chem. Pharm. Bull. 2013, 61, 1197. https://doi.org/10.1248/cpb.c13-00456
5. M. Hayashi, Y. Sasano, M. Shibuya, Y. Iwabuchi, Chem. Pharm. Bull. 2011, 59, 1570. https://doi.org/10.1248/cpb.59.1570
6. M. Hayashi, M. Shibuya, Y. Iwabuchi, J. Org. Chem. 2012, 77, 3005. https://doi.org/10.1021/jo300088b
7. M. Shibuya, T. Shibuta, Y. Iwabuchi, Org. Lett. 2012, 14, 5010. https://doi.org/10.1021/ol3021435