Peroxy Acids and Esters
Sodium percarbonate allows the convenient preparation of peroxy acids from acid chlorides, and even from the acids themselves.
Anhydrous [2-percarboxyethyl] functionalized silica is an advantageous oxidant for epoxidation of olefins. The acidic silica surface does not catalyze ring-opening reactions except for particularly activated styrene oxide. Alkenes carrying hydroxyl groups react with silica-supported peracid faster than unsubstituted alkenes. Products can be isolated after simple filtration and solvent evaporation.
R. Mello, A. Alcalde-Aragonés, M. E. González Núńez, G. Asensio, J. Org. Chem., 2012, 77, 6409-6413.
Addition of perfluoro-tert-butyl alcohol to a toluene solution of alkene and cyclopropyl malonoyl peroxide increases the rate of dihydroxylation product formation and the stereoselectivity observed, providing a simple and effective method for acceleration of this important class of reaction. Basic hydrolysis of the crude reaction mixture provides access to syn-diols in high yield and stereoselectivity.
S. Picon, M. Rawling, M. Campbell, N. C. O. Tomkinson, Org. Lett., 2012, 14, 6250-6253.
A mild protocol for the α-C-H cyanation of tertiary aliphatic, benzylic, and aniline-type substrates and complex substrates tolerates a broad range of fuctional groups, including various heterocycles and ketones, amides, olefins, and alkynes. The presented catalyst system especially tolerates functional groups that typically react with free radicals, suggesting an alternative reaction pathway.
O. Yilmaz, C. Dengiz, M. H. Emmert, J. Org. Chem., 2021, 86, 2489-2498.
The use of nonanebis(peroxoic acid) enables a regio- and chemoselective oxidation of aromatic amines hindered with an ortho substituent to the corresponding nitro compounds, except for anilines ortho-substituted with amino groups (NH2, NHR) or hydroxyl groups, where H-bonding between an hydrogen of the adjacent group and an oxygen atom from the diperoxy acid directs the oxidation.
V. V. Patil, G. S. Shankarling, J. Org. Chem., 2015, 80, 7876-7883.
The oxidation of malononitrile derivatives with peracid in methanol proceeds with loss of the cyano groups to yield methyl esters in high yield. The method was applied to a variety of malononitrile derivatives, some of which were prepared by Pd- or Ir-catalyzed asymmetric allylic substitution.
S. Förster, O. Tverskoy, G. Helmchen, Synlett, 2008, 2803-2806.