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Oxidative Cleaveage of Glycols
Fri Jun 17, 2005 12:00 am |
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1,2-Glycols are easily cleaved under mild conditions and in good yield with periodic
acid or lead tetraacetate.164 The products are 2 mol of aldehyde, or 2 mol of ketone,
or 1 mol of each, depending on the groups attached to the two carbons. The yields are
so good that alkenes are often converted to glycols (15-46), and then cleaved with
HIO4 or Pb(OAc)4 rather than being cleaved directly with ozone (19-9) or dichromate
or permanganate (19-10). A number of other oxidizing agents also give the
same products, among them165 activated MnO2,166 and pyridinium chlorochromate.
167 Permanganate, dichromate, and several other oxidizing agents168 also
cleave glycols, giving carboxylic acids rather than aldehydes, but these reagents are
seldom used synthetically. Electrochemical oxidation is an efficient method, and is
useful not only for diols, but also for their mono- and dimethoxy derivatives.169
The two reagents (periodic acid and lead tetraacetate) are complementary, since
periodic acid is best used in water and lead tetraacetate in organic solvents. When
three or more OH groups are located on adjacent carbons, the middle one (or ones) is
converted to formic acid.
Similar cleavage is undergone by other compounds that contain oxygens or
nitrogens on adjacent carbons:
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References
166 Adler, E.; Becker, H. Ada Chem. Scand, 1961, 15, 849; Ohloff, G.; Giersch, W. Angew.
Chem. Int. Ed. Engl, 1973, 12, 401.
167 Cisneros, A.; Fernandez, S.; Hernandez, J.E. Synth. Comm., 1982, 12, 833.
168 For a list of reagents, with references, see Ref. 21, p. 836.
169 For a review, see Shono, T. Electroorganic Chemistry as a New Tool in Organic Synthesis;
Springer: NY, 1984, p. 31. See also Ruholl, H.; Schafer, H.J. Synthesis, 1988, 54.
l 7 0Gagnon, J.L.; Zajac Jr., W.W. Tetrahedron Lett., 1995, 36, 1803.
171 See, for example, Ogata, Y.; Sawaki, Y; Shiroyama, M. / Org. Chem., 1977, 42, 4061.
l 7 2Nagarkatti, J.P.; Ashley, K.R. Tetrahedron Lett, 1973, 4599.
173 Kore, A.R.; Sagar, A.D.; Salunkhe, M.M. Org. Prep. Proceed. Int., 1995, 27, 373.
l 7 4Criegee, R.; Kraft, L.; Rank, B. Liebigs Ann. Chem., 1933, 507, 159. For reviews, see
Waters, W.A. Ref. 2, p. 72; Stewart, R. Ref. 2, p. 97.
175 For example, see Criegee, R.; Hoger, E.; Huber, G.; Kruck, P.; Marktscheffel, F.;
Schellenberger, H. Liebigs Ann. Chem., 1956, 599, 81.
176 Buist, G.J.; Bunton, C.A.; Hipperson, W.C.P /. Chem. Soc. B, 1971, 2128.
177 Angyal, S.J.; Young, R.J. /. Am. Chem. Soc, 1959, 81, 5251.
...............I found this to be an interesting reaction with possibilities ...........java |
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