ORGANIC
LETTERS
2012
Vol. 14, No. 19
5010–5013
Nitroxyl Radical/PhI(OAc)2: One-Pot
Oxidative Cleavage of Vicinal Diols
to (Di)Carboxylic Acids
Masatoshi Shibuya,*,† Takuro Shibuta, Hayato Fukuda, and Yoshiharu Iwabuchi*
Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences,
Tohoku University, 6-3 Aobayama, Sendai 980-8578, Japan
m-shibu@ps.nagoya-u.ac.jp; y-iwabuchi@m.tohoku.ac.jp
Received August 1, 2012
ABSTRACT
A mild and user-friendly one-pot oxidative cleavage of vicinal diols to their corresponding (di)carboxylic acids using AZADOs and PhI(OAc)2 is
described. 1,2-Diols and 2,3-diols as well as 1,2,3-triol gave one- or two-carbon-unit-shorter carboxylic acids. Internal vicinal diols also smoothly
underwent one-pot oxidative cleavage to afford the corresponding dicarboxylic acids. Cyclic vicinal diols are converted to their corresponding
open-form dicarboxylic acids.
The oxidativecleavageofvicinal diolstothe correspond-
ing carbonyl compounds is a useful transformation, offer-
ing design latitude in organic synthesis. Typically, this
transformation is conducted using hypervalent iodine
reagents, i.e., NaIO4, HIO4, PhI(OAc)2,1,2 and lead tetra-
mild conditions.4 However, large excess amounts of NMO
and precious rare metals are required. In the preceding
letter, we disclosed the 1-methyl-2-azaadamantane N-oxyl
(1-Me-AZADO)(3)/NaOCl/NaClO2 method for one-pot
oxidative cleavage from 1,2-diols to one-carbon-unit-
shorter carboxylic acids, which offered mild, clean, and
transition-metal-free oxidative dehomologation.5 However,
this method is specific to terminal vicinal diols. To expand the
3
acetate Pb(OAc)4 to obtain the intended aldehydes/
ketones in a dehomologated or ring-opening fashion. To
prepare a corresponding (di)carboxylic acid, an additional
oxidation from a (di)aldehyde to a (di)carboxylic acid is
required. Moreover, the lability of aldehydesoften causes a
decline in overall yield from a diol to its corresponding
(di)carboxylic acid. From these points of view, one-pot
oxidative cleavage from vicinal diols to their correspond-
ing (di)carboxylic acids is a promising reaction to improve
the efficiency of organic synthesis.
Recently, Stark et al. have developed a practical one-pot
oxidative cleavage using catalytic amounts of tetrapropyl-
ammonium perruthenate (TPAP) together with N-methyl-
morpholine N-oxide (NMO) as a stoichiometric oxidant,
which can be applied to a broad range of vicinal diols under
(4) (a) Schmidt, A.-K. C.; Stark, C. B. W. Org. Lett. 2011, 13, 5788–
5791. (b) Schmidt, A.-K. C.; Stark, C. B. W. Org. Lett. 2011, 13, 4164–
4167.
(5) Shibuya, M.; Doi, R.; Shibuta, T.; Uesugi, S.; Iwabuchi, Y. Org
Lett. 2012, DOI: 10.1021/ol3021429.
(6) (a) de Nooy, A. E. J.; Besemer, A. C.; van Bekkum, H. Synthesis
1996, 1153–1174. (b) Sheldon, R. A.; Arends, I. W. C. E. Adv. Synth.
Catal. 2004, 346, 1051–1071. (c) Vogler, T.; Studer, A. Synthesis 2008,
1979–1993. (d) Bobbitt, J. M.; Brockner, C.; Merbouh, N. Org. React.
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2010, 14, 245–251. (f) Tebben, L.; Studer, A. Angew. Chem., Int. Ed.
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(7) (a) Shibuya, M.; Tomizawa, M.; Suzuki, I.; Iwabuchi, Y. J. Am.
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Sasano, Y.; Iwabuchi, Y. J. Org. Chem. 2009, 74, 4619–4622.
(c) Hayashi, M.; Sasano, Y.; Nagasawa, S.; Shibuya, M.; Iwabuchi, Y.
Chem. Pharm. Bull. 2011, 59, 1570–1573. (d) Shibuya, M.; Osada, Y.;
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(f) Hayashi, M.; Shibuya, M.; Iwabuchi, Y. Org. Lett. 2012, 14, 154–157.
(g) Hayashi, M.; Shibuya, M.; Iwabuchi, Y. J. Org. Chem. 2012, 77,
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† Present address: Department of Basic Medicinal Sciences, Graduate
School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya
464-8601, Japan.
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r
10.1021/ol3021435
Published on Web 09/19/2012
2012 American Chemical Society