Enantioselective catalytic epoxidation of nonfunctionalized prochiral olefins by dissymmetric chiral Schiff base complexes of Mn(III) and Ru(III) metal ions II

Asymmetric Biomimetic Oxidations

“…77 Ruthenium(IH) complexes with a dissymmetric Schiff base containing the 1,2-diaminocyclohexane moiety have been evaluated for the epoxidation 13 of cis-, trans-and terminal olefins (styrene) by iodosylbenzene. 78,79 Only moderate enantiomeric excesses were obtained, in the same range as those observed with the manganese(III) analogues under similar conditions. Chromium(III) salen complexes associated with PhIO, which are less efficient for the epoxidation of conjugated olefins, were found to exhibit interesting solvent-dependent stereochemisty (better ee's with toluene than with acetonitrile).…”

Performance of dimethyl dioxirane/nano-TiO2 on epoxidation of polybutadiene and hydroxyl terminated polybutadiene

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Polybutadiene and hydroxyl terminated polybutadiene (HTPB) were epoxidized using in situ-generated dimethyl dioxirane (DMD) as an oxidant in the presence of nano-TiO 2 at 25 C. Reaction time and different percentages of catalyst/Oxone 1 (w/w) were also examined. The capability of different kinds of double bonds to be epoxidized was studied in detail at various reaction times, and the products were characterized using nuclear magnetic resonance ( 1 HNMR), 13 CNMR, and Fourier transform infrared (FT-IR) techniques, with no side reaction being detected. The results indicate that using nano-TiO 2 as a catalyst increases the epoxidation yield, especially of cis double bonds.

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Aldol Condensation Reactions Effectively Catalysed by Lewis Acid

“…12 Thus, the synthesis was carried out by refluxing ketopinic acid 1 with the R,R-1,2-Diaminocyclohexane 2 in the presence of a catalytic amount of glacial acetic acid, using chloroform as solvent (Scheme 1). Condensation of ketopinic acid (2 equiv.…”