1. Kozhevnikov, I.V. Chem. Rev. 1998, 98, 171–198; Mizuno, N.; Misono, M. Chem. Rev. 1998, 98, 199–217.
2. Piqueml, J.-Y.; Manoli, J.-M.; Beunier, P.; Ensuque, A.; Tougne, P.; Legrand, A.-P.; Bregeault, J.-M. Microporous Mesoporous Mater. 1999, 29, 291–304; Neumann, R.; Levin-Elad, M. J. Catal. 1997, 166, 206–217; Kumar, R.; Pais, G. C. G.; Pandey, B.; Kumar, P. J. Chem. Soc., Chem. Commun. 1995, 1315–1316; Bhaumik, A.; Tatsumi, T. J. Chem. Soc., Chem. Commun. 1998, 463–464; Neumann, R.; Chava, M.; Levin, M. J. Chem. Soc., Chem. Commun. 1993, 1685–1687; Zhang, Z.; Suo, J.; Zhang, X.; Li, S. J. Chem. Soc., Chem. Commun. 1998, 241–242; Laar, F.v.; Vos, D. D.; Vanoppen, D.; Sels, B.; Jacobs, P. A.; Guerzo, A. D.; Pierard, F.; Mesmaeker, A. K.-D. J. Chem. Soc., Chem. Commun. 1998, 267–268; Sels, B. F.; De Vos, D. E.: Jacobs, P. A. Tetrahedron Lett. 1996, 47, 8557–8560.
3. Tungstic acid is a well-known, conventional catalyst for H2O2-epoxidation of CC double bonds in aqueous solution among numerous polyoxometalate catalysts. Prat D.; Lett, R. Tetrahedron Lett. 1986, 27, 707–710; Prat, D.; Delpech, B.; Lett, R. Tetrahedron Lett. 1986, 27, 711–714; Stevens, H. C.; Kaman, A. J. J. Am. Chem. Soc. 1965, 87, 734–737.
4. In most cases, urea–H2O2 have been used under solid–liquid heterogeneous conditions with an organic solvent; D. Cosgrove, W, Jones, J. Chem. Soc., Chem. Commun. 1994, 2255–2256; Adam, W.; Mitchell, C. M. Angew. Chem., Int. Ed. Engl. 1996, 35, 533–535; Adam, W.; Kumar, R.; Reddy, T. R; Renz, M. Angew. Chem., Int. Ed. Engl. 1996, 35, 880–882.
5. Venturello, C.; D'Aloiso, R. J. Org. Chem. 1988, 53, 1553–1557; Venturello, C.; D'Aloiso, R.; Bart, J. C.; Ricci, M. J. Mol. Catal. 1985, 32, 107–110; Ishii, Y.; Yamawaki, K.; Yoshida, T.; Ura, T.; Ogawa, M. J. Org. Chem. 1987, 52, 1868–1870; Aubry, C.; Chottard, G.; Platzer, N.; Bregeault, J.-M.; Thouvenot, R.; Chauveau, F.; Huet, C.; Ledon, H. Inorg. Chem. 1991, 30, 4409–4415; Dengel, C.; Griffith, W. P.; Parkin, B. C. J. Chem. Soc., Dalton Trans. 1993, 2683–2688.