Homogeneous [Ru(III)(Me3tacn)Cl3]-catalyzed alkene cis-dihydroxylation with aqueous hydrogen peroxide.
A simple and green method that uses [Ru(Me3tacn)Cl3] (1; Me3tacn = N,N',N''-trimethyl-1,4,7-triazacyclononane) as catalyst, aqueous H2O2 as the terminal oxidant, and Al2O3 and NaCl as additives is effective in the cis-dihydroxylation of alkenes in aqueous tert-butanol. Unfunctionalized alkenes, including cycloalkenes, aliphatic alkenes, and styrenes (14 examples) were selectively oxidized to their corresponding cis-diols in good to excellent yield (70-96%) based on substrate conversions of up to 100%. The preparation of cis-1,2-cycloheptanediol (119 g, 91% yield) and cis-1,2-cyclooctanediol (128 g, 92% yield) from cycloheptene and cyclooctene, respectively, on the 1-mol scale can be achieved by scaling up the reaction without modification. Results from Hammett correlation studies on the competitive oxidation of para-substituted styrenes (rho = -0.97, R = 0.988) and the detection of the cycloadduct [(Me3tacn)ClRuHO2(C8H14)]+ by ESI-MS for the 1-catalyzed oxidation of cyclooctene to cis-1,2-cyclooctanediol are similar to those of the stoichiometric oxidation of alkenes by cis-[(Me3tacn)(CF3CO2)Ru(VI)O2]+ through [3+2] cycloaddition (W.-P. Yip, W.-Y. Yu, N. Zhu, C.-M. Che, J. Am. Chem. Soc. 2005, 127, 14239).
Yip
Wing-Ping
WP
Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Ho
Chi-Ming
CM
Zhu
Nianyong
N
Lau
Tai-Chu
TC
Che
Chi-Ming
CM
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006900:Hydroxylation; D010084:Oxidation-Reduction; D017975:Ruthenium Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D000475:Alkenes; D017975:Ruthenium Compounds; D014867:Water; D006861:Hydrogen Peroxide